{"id":13616,"date":"2025-10-03T11:42:30","date_gmt":"2025-10-03T10:42:30","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=13616"},"modified":"2026-02-13T05:32:19","modified_gmt":"2026-02-13T05:32:19","slug":"interior-of-the-earth-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/10\/03\/interior-of-the-earth-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Interior of the Earth Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">1. The study of Earth\u2019s interior is primarily based on_____________.<\/mark><\/strong><br>A) Direct drilling<br>B) Volcanic activity<br>C) Seismic waves<br>D) Fossils<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C <\/b><BR>\n<b>Explanation:<\/b>   Since direct access is limited, scientists study earthquake-generated seismic waves to infer Earth\u2019s interior.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">2. The average radius of the Earth is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 3,276 km<br>B) 5,276 km<br>C) 6,371 km<br>D) 7,500 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The Earth\u2019s mean radius is approximately 6,371 km.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">3. The innermost layer of the Earth is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  The solid inner core is Earth\u2019s deepest layer, mainly composed of iron and nickel.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">4. The Mohorovi\u010di\u0107 discontinuity (Moho) separates<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Mantle and outer core<br>B) Crust and mantle<br>C) Inner core and outer core<br>D) Lithosphere and asthenosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The Moho marks the boundary between Earth\u2019s crust and mantle.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">5. The core of the Earth is mainly composed of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Oxygen and silicon<br>B) Iron and nickel<br>C) Magnesium and aluminum<br>D) Sodium and potassium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Earth\u2019s core is metallic, made primarily of iron and nickel (NiFe).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">6. The outer core of Earth is in which state?<\/mark><\/strong><br>A) Solid<br>B) Liquid<br>C) Semi-solid<br>D) Gas<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The outer core is liquid metal, responsible for Earth\u2019s magnetic field.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">7. The inner core of Earth is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Solid<br>B) Liquid<br>C) Semi-molten<br>D) Gas<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Despite high temperatures, pressure keeps the inner core solid.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">8. The crust is thickest under<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Continents<br>B) Oceans<br>C) Islands<br>D) Rivers<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Continental crust averages 35 km thick (up to 70 km under mountains), while oceanic crust averages 5\u201310 km.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">9. The crust is primarily composed of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Basalt and granite<br>B) Iron and nickel<br>C) Carbonates and sulphates<br>D) Argon and nitrogen<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Continental crust is granitic, while oceanic crust is basaltic.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">10. The mantle extends to a depth of about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 30 km<br>B) 100 km<br>C) 2,900 km<br>D) 5,200 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The mantle lies between the crust and core, up to ~2,900 km deep.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">11. The Gutenberg discontinuity separates<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Crust and mantle<br>B) Mantle and outer core<br>C) Outer core and inner core<br>D) Lithosphere and asthenosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Gutenberg discontinuity lies at ~2,900 km depth between mantle and outer core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">12. The Lehmann discontinuity lies between<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Crust and mantle<br>B) Mantle and outer core<br>C) Outer core and inner core<br>D) Lithosphere and asthenosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Lehmann discontinuity (at ~5,150 km depth) separates the liquid outer core from solid inner core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">13. Which part of Earth generates its magnetic field?<\/mark><\/strong><br>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Movement of liquid iron in the outer core creates Earth\u2019s magnetic field.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">14. The lithosphere includes<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Crust only<br>B) Mantle only<br>C) Crust and uppermost mantle<br>D) Core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The rigid lithosphere consists of crust plus upper mantle, broken into tectonic plates.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">15. Beneath the lithosphere lies<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Asthenosphere<br>B) Mesosphere<br>C) Outer core<br>D) Moho<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  The asthenosphere is a ductile, partially molten layer on which lithospheric plates float.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">16. The average density of Earth is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 2.5 g\/cm\u00b3<br>B) 3.3 g\/cm\u00b3<br>C) 5.5 g\/cm\u00b3<br>D) 7.9 g\/cm\u00b3<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Earth\u2019s mean density is 5.5 g\/cm\u00b3, higher than surface rocks, indicating a dense metallic core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">17. The oceanic crust is mainly composed of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Granite<br>B) Basalt<br>C) Limestone<br>D) Sandstone<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Oceanic crust is basaltic, denser than continental granite.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">18. The continental crust is mainly composed of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Basalt<br>B) Granite<br>C) Iron<br>D) Gabbro<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Continental crust is granitic, lighter than oceanic crust.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">19. Which seismic waves cannot pass through liquid?<\/mark><\/strong><br>A) P-waves<br>B) S-waves<br>C) L-waves<br>D) Surface waves<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  S-waves (shear waves) cannot travel through liquids, proving the outer core is liquid.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">20. Which seismic waves are the fastest?<\/mark><\/strong><br>A) P-waves<br>B) S-waves<br>C) Surface waves<br>D) L-waves<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Primary (P) waves are fastest and arrive first at seismic stations.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">21. The depth of the Moho discontinuity beneath continents is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 5\u201310 km<br>B) 20\u201330 km<br>C) 35 km average<br>D) 100 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The Moho is deeper under continents (~35 km) than oceans (~5\u201310 km).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">22. The asthenosphere lies at what depth?<\/mark><\/strong><br>A) 0\u201310 km<br>B) 30\u2013100 km<br>C) 100\u2013400 km<br>D) 2,900\u20135,100 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Asthenosphere is a weak, ductile layer of upper mantle at ~100\u2013400 km depth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">23. The temperature at Earth\u2019s center is estimated to be<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 500\u00b0C<br>B) 1,500\u00b0C<br>C) 3,000\u00b0C<br>D) 5,000\u20136,000\u00b0C<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  The inner core reaches ~5,000\u20136,000\u00b0C, similar to Sun\u2019s surface.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">24. The term &#8220;SIAL&#8221; refers to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Oceanic crust (Silica + Magnesium)<br>B) Continental crust (Silica + Aluminum)<br>C) Mantle composition<br>D) Core composition<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Continental crust is rich in silica and aluminum, hence &#8220;SIAL&#8221;.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">25. The term &#8220;SIMA&#8221; refers to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Core composition<br>B) Oceanic crust (Silica + Magnesium)<br>C) Continental crust<br>D) Lithosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Oceanic crust is mainly basaltic, rich in silica and magnesium \u2013 &#8220;SIMA&#8221;.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">26. Which is the thinnest layer of the Earth?<\/mark><\/strong><br>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  The crust is Earth\u2019s outermost and thinnest layer (5\u201370 km).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">27. The average thickness of oceanic crust is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 70 km<br>B) 50 km<br>C) 30 km<br>D) 5\u201310 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Oceanic crust is very thin compared to continental crust.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">28. Which part of the Earth is responsible for volcanic eruptions?<\/mark><\/strong><br>A) Inner core<br>B) Outer core<br>C) Mantle<br>D) Crust<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Magma originates from the mantle and erupts through the crust.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">29. The average thickness of continental crust is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 5 km<br>B) 35 km<br>C) 70 km<br>D) 100 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Continental crust is ~35 km thick, reaching up to 70 km under mountains.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">30. Which element is the most abundant in Earth\u2019s crust?<\/mark><\/strong><br>A) Oxygen<br>B) Silicon<br>C) Iron<br>D) Magnesium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Oxygen makes up ~47% of Earth\u2019s crust by weight.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">31. Which element is the second most abundant in Earth\u2019s crust?<\/mark><\/strong><br>A) Silicon<br>B) Iron<br>C) Magnesium<br>D) Calcium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Silicon is ~28% of the crust, mainly in silicate minerals.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">32. Which two elements together make up about 75% of Earth\u2019s crust?<\/mark><\/strong><br>A) Iron and nickel<br>B) Silicon and oxygen<br>C) Magnesium and aluminum<br>D) Calcium and sodium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Together they form silicates, the dominant crustal minerals.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">33. The \u201cConrad Discontinuity\u201d separates<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Continental crust and oceanic crust<br>B) Upper and lower mantle<br>C) Lithosphere and asthenosphere<br>D) Outer and inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  It separates the granitic upper crust from basaltic lower crust.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">34. The \u201cRepetti Discontinuity\u201d separates<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Crust and mantle<br>B) Mantle and outer core<br>C) Upper and lower mantle<br>D) Outer and inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C <\/b><BR>\n<b>Explanation:<\/b>  It lies at ~1,000 km depth, dividing upper and lower mantle.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>35. Which layer of Earth is known as the \u201cmesosphere\u201d (not atmosphere)?<\/strong><br><\/mark>A) Outer mantle<br>B) Lower mantle<br>C) Inner core<br>D) Crust<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The lower mantle (660\u20132,900 km depth) is sometimes called the mesosphere.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>36. Which layer of the Earth is directly involved in plate tectonic movement?<\/strong><br><\/mark>A) Inner core<br>B) Outer core<br>C) Lithosphere<br>D) Asthenosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D <\/b><BR>\n<b>Explanation:<\/b>  The ductile asthenosphere allows lithospheric plates to move over it.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>37. Earthquake shadow zones are formed because<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) S-waves cannot pass through liquid outer core<br>B) P-waves travel straight lines<br>C) Crust blocks the waves<br>D) Inner core absorbs waves<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A <\/b><BR>\n<b>Explanation:<\/b>  This creates an S-wave shadow zone, while P-waves bend, creating their own shadow zone.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">38. The seismic shadow zone of P-waves lies between<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 0\u00b0\u2013103\u00b0<br>B) 103\u00b0\u2013143\u00b0<br>C) 143\u00b0\u2013180\u00b0<br>D) 0\u00b0\u201390\u00b0<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  P-waves are refracted at the core-mantle boundary, creating a 103\u00b0\u2013143\u00b0 shadow zone.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">39. The density of Earth increases with depth due to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Temperature decrease<br>B) Pressure increase<br>C) Composition change<br>D) Both b and c<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D <\/b><BR>\n<b>Explanation:<\/b>  Density rises from crust (~2.7 g\/cm\u00b3) to core (~13 g\/cm\u00b3) because of pressure and composition.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">40. Which discontinuity marks the boundary between lithosphere and asthenosphere?<\/mark><\/strong><br>A) Moho<br>B) Repetti<br>C) Conrad<br>D) Low-velocity zone<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  The lithosphere-asthenosphere boundary is identified by a low-velocity zone of seismic waves.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">41. The most abundant metal in Earth\u2019s crust is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Iron<br>B) Aluminum<br>C) Magnesium<br>D) Calcium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Aluminum is the most abundant metallic element in the crust (~8%).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">42. The most abundant element in Earth as a whole is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Oxygen<br>B) Silicon<br>C) Iron<br>D) Nickel<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C <\/b><BR>\n<b>Explanation:<\/b>  Iron dominates the core, making it the most abundant element in the entire Earth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>43. Which layer is responsible for convection currents driving plate tectonics?<\/strong><br><\/mark>A) Inner core<br>B) Asthenosphere<br>C) Crust<br>D) Lithosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Convection currents in the asthenosphere move tectonic plates.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>44. The Kola Superdeep Borehole (Russia) reached a depth of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) 2 km<br>B) 5 km<br>C) 12 km<br>D) 25 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  It\u2019s the deepest artificial borehole, far less than Earth\u2019s total crust thickness.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">45. The D\u2019\u2019 (D double-prime) layer is located<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) At Moho discontinuity<br>B) At crustal base<br>C) At the core-mantle boundary<br>D) Within the asthenosphere<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  D\u2019\u2019 is a thin boundary layer above the outer core (~2,900 km depth).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>46. Which layer of Earth is about 2,900 km thick?<\/strong><br><\/mark>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>   The mantle extends from ~30 km to 2,900 km depth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">47. The thickness of the outer core is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 100 km<br>B) 700 km<br>C) 2,200 km<br>D) 3,500 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The outer core is ~2,200 km thick, liquid, extending from 2,900\u20135,100 km.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">48. The thickness of the inner core is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 200 km<br>B) 500 km<br>C) 1,200 km<br>D) 2,500 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The solid inner core has a radius of ~1,200\u20131,220 km.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">49. The asthenosphere is characterized by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Brittle rocks<br>B) Partial melting and ductility<br>C) Solid iron<br>D) Volcanic deposits<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>   Rocks in the asthenosphere are soft and flow slowly.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>50. Which discontinuity separates the upper and lower mantle?<\/strong><br><\/mark>A) Lehmann<br>B) Gutenberg<br>C) Repetti<br>D) Conrad<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The Repetti discontinuity (~1,000 km depth) marks this boundary.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>51. The primary source of information about Earth\u2019s interior comes from<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) Volcanic rocks<br>B) Mines<br>C) Seismic waves<br>D) Ocean drilling<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Seismology provides the most reliable data about Earth\u2019s internal structure.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>52. The rocks of the upper mantle are mainly<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) Granite<br>B) Basalt<br>C) Peridotite<br>D) Sandstone<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>   The mantle is dominated by peridotite, rich in olivine and pyroxene.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">53. The temperature at the Moho discontinuity is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 200\u00b0C<br>B) 400\u00b0C<br>C) 800\u00b0C<br>D) 1,000\u00b0C<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Temperatures at the crust\u2013mantle boundary are around 1,000\u00b0C.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>54. The seismic discontinuity at 660 km depth is associated with<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) Moho<br>B) Repetti<br>C) Mantle transition zone<br>D) Lehmann<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  At ~660 km, mineral transformations mark the mantle\u2019s upper-lower boundary.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>55. The Earth&#8217;s crust makes up only about what percentage of Earth\u2019s volume?<\/strong><br><\/mark>A) 1%<br>B) 5%<br>C) 10%<br>D) 25%<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   Crust is extremely thin compared to mantle and core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>56. The lower mantle is also called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) Asthenosphere<br>B) Mesosphere<br>C) Lithosphere<br>D) D-layer<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The lower mantle (660\u20132,900 km depth) is termed the mesosphere.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">57. The Kola Superdeep Borehole could penetrate only a fraction of the crust. Its depth was<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 5 km<br>B) 8 km<br>C) 12 km<br>D) 20 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C <\/b><BR>\n<b>Explanation:<\/b>  It reached 12.2 km, less than 0.2% of Earth\u2019s radius.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>58. Which region of Earth is responsible for volcanism and earthquakes?<\/strong><br><\/mark>A) Crust and upper mantle<br>B) Outer core<br>C) Inner core<br>D) Lower mantle<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Tectonic activity originates in the lithosphere and asthenosphere.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>59. The asthenosphere plays a key role in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) Plate tectonics<br>B) Ocean currents<br>C) Volcanic gases<br>D) Atmosphere formation<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Its ductility enables lithospheric plates to move.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>60. Which method helps determine the thickness of the crust?<\/strong><br><\/mark>A) Drilling<br>B) Gravity survey<br>C) Seismic survey<br>D) Magnetic survey<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Seismic waves reveal the depth of discontinuities like the Moho.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>61. What percentage of Earth\u2019s volume is occupied by the mantle?<\/strong><br><\/mark>A) 50%<br>B) 67%<br>C) 83%<br>D) 90%<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Mantle is the largest layer, making up about 83% of Earth\u2019s volume.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>62. The inner core is solid because<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) It is colder<br>B) High pressure prevents melting<br>C) It has less iron<br>D) It is crystallized basalt<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>   Enormous pressure keeps the core solid despite high temperatures.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">63. The outer core extends from a depth of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 1,000\u20132,000 km<br>B) 2,900\u20135,150 km<br>C) 3,500\u20136,371 km<br>D) 5,200\u20136,371 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The liquid outer core lies between mantle and solid inner core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">64. The solid inner core has a radius of about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 500 km<br>B) 1,220 km<br>C) 2,500 km<br>D) 3,000 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The inner core\u2019s radius is ~1,220 km.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">65. Earth\u2019s magnetic field protects us mainly from<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Meteors<br>B) Solar wind<br>C) UV radiation<br>D) Earthquakes<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B <\/b><BR>\n<b>Explanation:<\/b>   The magnetosphere deflects harmful charged particles from the Sun.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">66. Which layer of Earth is least accessible to direct study?<\/mark><\/strong><br>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D <\/b><BR>\n<b>Explanation:<\/b>   The inner core is inaccessible due to depth and pressure; only indirect evidence exists.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">67. The geotherm refers to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Seismic wave velocity<br>B) Variation of temperature with depth<br>C) Rock density<br>D) Earth\u2019s pressure gradient<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The geotherm shows how temperature increases with depth inside Earth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">68. Which zone is known as the &#8220;Low Velocity Zone&#8221; (LVZ)?<\/mark><\/strong><br>A) Inner core<br>B) Asthenosphere<br>C) Moho<br>D) Lower mantle<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Seismic waves slow down in the partially molten asthenosphere.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">69. What is the estimated pressure at Earth\u2019s center?<\/mark><\/strong><br>A) 100,000 atm<br>B) 1 million atm<br>C) 3 million atm<br>D) 3.5\u20133.6 million atm<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Extreme pressure exists at the inner core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">70. Which discontinuity is found at ~100 km depth?<\/mark><\/strong><br>A) Moho<br>B) Conrad<br>C) Lithosphere\u2013asthenosphere boundary<br>D) Gutenberg<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The L\u2013A boundary lies around 80\u2013120 km.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">71. The thickness of Earth\u2019s lithosphere varies between<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 1\u20135 km<br>B) 10\u201350 km<br>C) 50\u2013200 km<br>D) 500\u20131,000 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Lithosphere thickness depends on tectonic setting.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>72. The seismic wave that travels through both solids and liquids is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) P-wave<br>B) S-wave<br>C) L-wave<br>D) R-wave<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   Primary (compressional) waves pass through all mediums.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>73. Which wave travels only through solid materials?<\/strong><br><\/mark>A) P-wave<br>B) S-wave<br>C) L-wave<br>D) R-wave<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Shear waves cannot move through liquids, hence blocked by outer core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">74. Earth\u2019s average crustal thickness is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 20 km<br>B) 30 km<br>C) 50 km<br>D) 100 km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>   Average crust thickness: ~35 km under continents, ~7 km under oceans.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">75. The mantle\u2019s composition is dominated by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Silica + Aluminum<br>B) Silica + Magnesium<br>C) Iron + Nickel<br>D) Calcium + Sodium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B <\/b><BR>\n<b>Explanation:<\/b>  The mantle is SIMA-rich, with silicate minerals of magnesium and iron.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">76. The boundary between crust and mantle is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Lehmann discontinuity<br>B) Gutenberg discontinuity<br>C) Moho discontinuity<br>D) Repetti discontinuity<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  The Mohorovi\u010di\u0107 discontinuity (Moho) separates Earth\u2019s crust and mantle.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">77. The density of the crust compared to the mantle is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Higher<br>B) Lower<br>C) Equal<br>D) Same at all depths<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Crust is lighter (2.7\u20133.0 g\/cm\u00b3), mantle is denser (~3.3\u20135.5 g\/cm\u00b3).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">78. Which part of the Earth has the lowest density?<\/mark><\/strong><br>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Crust is the lightest layer, made mostly of granitic and basaltic rocks.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">79. Which layer is believed to be the source of basaltic magma?<\/mark><\/strong><br>A) Crust<br>B) Upper mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Partial melting in the upper mantle (asthenosphere) produces basaltic magma.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">80. The mantle is made up predominantly of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Peridotite<br>B) Granite<br>C) Basalt<br>D) Gabbro<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Peridotite (olivine-rich rock) dominates mantle composition.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">81. Earth\u2019s internal heat is mainly due to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Primordial heat + Radioactive decay<br>B) Solar radiation<br>C) Meteorite impacts only<br>D) Atmospheric greenhouse effect<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   Leftover heat from formation and isotope decay maintain Earth\u2019s heat.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">82. The D\u02ba (D double-prime) layer is located<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) At crust\u2013mantle boundary<br>B) Within lithosphere<br>C) Just above core\u2013mantle boundary<br>D) In the outer core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>   D\u02ba lies at ~2,700\u20132,900 km depth, at base of the mantle.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">83. The average density of mantle rocks is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 2.5 g\/cm\u00b3<br>B) 3.3 g\/cm\u00b3<br>C) 5.5 g\/cm\u00b3<br>D) 10 g\/cm\u00b3<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Mantle density averages ~3.3 g\/cm\u00b3, increasing with depth.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">84. Which discontinuity is at ~5,100 km depth?<\/mark><\/strong><br>A) Moho<br>B) Gutenberg<br>C) Repetti<br>D) Lehmann<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Lehmann discontinuity separates liquid outer core from solid inner core.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">85. Which statement is correct about the outer core?<\/mark><\/strong><br>A) Solid, rich in silicon<br>B) Solid, rich in iron<br>C) Liquid, rich in iron and nickel<br>D) Semi-solid, rich in basalt<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>   The outer core is molten Fe\u2013Ni alloy, creating Earth\u2019s magnetic field.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">86. The asthenosphere is important because<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) It forms the rigid plates<br>B) It is the source of convection currents<br>C) It is the densest layer<br>D) It produces seismic shadow zones<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Heat-driven convection in asthenosphere drives plate movements.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">87. Which layer has the maximum thickness?<\/mark><\/strong><br>A) Crust<br>B) Mantle<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Mantle is ~2,900 km thick, the thickest Earth layer.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">88. Which waves are the fastest seismic waves?<\/mark><\/strong><br>A) P-waves<br>B) S-waves<br>C) L-waves<br>D) Surface waves<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>   Primary waves move fastest, ~6\u201314 km\/s.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">89. The inner core is mostly composed of<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Granite<br>B) Peridotite<br>C) Iron and nickel<br>D) Silica and magnesium<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Core is NiFe-rich, mostly iron (~85%) and nickel.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">90. The &#8220;shadow zone&#8221; proves that<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Mantle is solid<br>B) Inner core is molten<br>C) Outer core is liquid<br>D) Crust is thin<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>   S-waves stop at outer core, and P-waves bend, forming shadow zones.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">91. Earth\u2019s magnetic field is generated by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Solidification of crust<br>B) Convection in outer core<br>C) Mantle conduction<br>D) Inner core crystallization<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  The geodynamo effect in liquid outer core produces the magnetic field.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">92. The temperature gradient inside Earth is about<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) 10\u00b0C\/km<br>B) 25\u201330\u00b0C\/km in crust<br>C) 50\u00b0C\/km<br>D) 100\u00b0C\/km<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>   This geothermal gradient applies in the upper crust.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">93. The innermost solid part of Earth is under what pressure?<\/mark><\/strong><br>A) 10,000 atm<br>B) 100,000 atm<br>C) 1 million atm<br>D) 3.5 million atm<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: D  <\/b><BR>\n<b>Explanation:<\/b>  Enormous pressure keeps the inner core solid.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">94. What is the estimated temperature at Earth\u2019s core?<\/mark><\/strong><br>A) 1,500\u00b0C<br>B) 3,000\u00b0C<br>C) 5,000\u20136,000\u00b0C<br>D) 10,000\u00b0C<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Similar to Sun\u2019s surface, core temperatures are ~6,000\u00b0C.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">95. Which layer is also called the \u201csima layer\u201d?<\/mark><\/strong><br>A) Continental crust<br>B) Oceanic crust<br>C) Mantle<br>D) Outer core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>  Oceanic crust is silica + magnesium (SIMA).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">96. Which layer is called the \u201csial layer\u201d?<\/mark><\/strong><br>A) Continental crust<br>B) Oceanic crust<br>C) Mantle<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Continental crust is silica + aluminum (SIAL).\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">97. Which part of Earth is described as \u201cplastic\u201d in behavior?<\/mark><\/strong><br>A) Lithosphere<br>B) Asthenosphere<br>C) Outer core<br>D) Inner core<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B <\/b><BR>\n<b>Explanation:<\/b>  Ductile rocks here allow plate movement.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">98. Which discontinuity was discovered using seismic data in 1909?<\/mark><\/strong><br>A) Moho<br>B) Gutenberg<br>C) Lehmann<br>D) Conrad<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: A  <\/b><BR>\n<b>Explanation:<\/b>  Mohorovi\u010di\u0107 discovered it by studying earthquake waves.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">99. The fluid outer core plays a major role in<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/mark><\/strong><br>A) Plate tectonics<br>B) Ocean currents<br>C) Magnetic field generation<br>D) Earthquakes<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: C  <\/b><BR>\n<b>Explanation:<\/b>  Convection in outer core drives the geodynamo.\n <\/p>\n<\/div>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong>100. The study of Earth\u2019s internal structure using seismic waves is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">_____________.<\/mark><\/strong><\/strong><br><\/mark>A) Geodesy<br>B) Seismology<br>C) Geomorphology<br>D) Petrology<\/p>\n\n\n\n<button class=\"acc\">Show Answer<\/button>\n<div class=\"pnl\">\n  <p style=\"font-size: 22px;\"><b> Answer: B  <\/b><BR>\n<b>Explanation:<\/b>   Seismology is the science of earthquake waves and Earth\u2019s interior.\n <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>1. The study of Earth\u2019s interior is primarily based on_____________.A) Direct drillingB) Volcanic activityC) Seismic wavesD) Fossils Show Answer Answer: C Explanation: Since direct access is limited, scientists study earthquake-generated seismic waves to infer Earth\u2019s interior. 2. The average radius of the Earth is about_____________.A) 3,276 kmB) 5,276 kmC) 6,371 kmD) 7,500 km Show Answer<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"[]"},"categories":[11121,14],"tags":[14408,14394,14407,14405,14389,14410,14388,14409,14401,14404,14400,14406,14396,14393,14395,14391,14398,14390,14397,11122,14402,14399,4029,5649,5623,14367,14348,14403,14392],"class_list":{"0":"post-13616","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-physical-geography","7":"category-geography","8":"tag-class-11-geography-mcqs","9":"tag-crust-mantle-core-mcqs","10":"tag-earth-interior-quiz-questions","11":"tag-geography-gk-questions","12":"tag-geography-mcqs-for-competitive-exams","13":"tag-geography-mcqs-for-ssc","14":"tag-geography-mcqs-with-answers","15":"tag-geography-one-liner-questions","16":"tag-geography-quiz-with-explanation","17":"tag-geology-mcqs-with-answers","18":"tag-interior-of-earth-gk-questions","19":"tag-interior-of-earth-questions-for-exams","20":"tag-interior-of-earth-upsc-questions","21":"tag-interior-of-the-earth-mcqs","22":"tag-interior-of-the-earth-mcqs-with-answers","23":"tag-interior-of-the-earth-mcqs-with-explanation","24":"tag-interior-of-the-earth-multiple-choice-questions","25":"tag-interior-of-the-earth-objective-questions","26":"tag-interior-of-the-earth-quiz-questions","27":"tag-interior-of-the-earth-top-100-mcqs-with-answer-and-explanation","28":"tag-interior-structure-of-earth-questions","29":"tag-layers-of-the-earth-mcqs","30":"tag-mcqs-adda","31":"tag-mcqs-for-pc-psi-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","32":"tag-mcqs-for-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","33":"tag-ncert-geography-mcqs","34":"tag-physical-geography-mcqs","35":"tag-physical-geography-questions-and-answers","36":"tag-top-100-interior-of-the-earth-mcqs"},"_links":{"self":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/13616","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/comments?post=13616"}],"version-history":[{"count":105,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/13616\/revisions"}],"predecessor-version":[{"id":47620,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/13616\/revisions\/47620"}],"wp:attachment":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/media?parent=13616"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/categories?post=13616"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/tags?post=13616"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}