1. The Earth is believed to have formed around—
a) 2.5 billion years ago
b) 3.2 billion years ago
c) 4.6 billion years ago
d) 6.2 billion years ago
Answer: c) 4.6 billion years ago
Explanation: Earth formed ~4.6 billion years ago from a solar nebula (gas and dust cloud).
2. Which hypothesis explains the origin of the Solar System from a nebula?
a) Catastrophic hypothesis
b) Nebular hypothesis
c) Binary star hypothesis
d) Tidal hypothesis
Answer: b) Nebular hypothesis
Explanation: The nebular hypothesis suggests the Sun and planets condensed from a rotating cloud of gas and dust.
3. Who first proposed the Nebular Hypothesis?
a) Immanuel Kant
b) Laplace
c) Copernicus
d) Galileo
Answer: a) Immanuel Kant
Explanation: Kant (1755) proposed the nebular hypothesis, later modified by Laplace.
4. The Earth’s layered structure developed due to—
a) Gravitational differentiation
b) External impacts
c) Solar wind
d) Tidal forces
Answer: a) Gravitational differentiation
Explanation: Heavy elements sank to form the core, while lighter materials rose to form the crust.
5. The earliest atmosphere of Earth mainly consisted of—
a) Oxygen and nitrogen
b) Hydrogen and helium
c) Carbon dioxide and methane
d) Nitrogen and argon
Answer: b) Hydrogen and helium
Explanation: The primitive atmosphere was composed of light gases, later lost due to solar winds.
6. The second atmosphere of Earth was dominated by—
a) Oxygen
b) Carbon dioxide, methane, ammonia, water vapor
c) Ozone
d) Nitrogen only
Answer: b) Carbon dioxide, methane, ammonia, water vapor
Explanation: Volcanic outgassing created a thick atmosphere without free oxygen.
7. The present-day atmosphere is known as—
a) Reducing atmosphere
b) Secondary atmosphere
c) Oxidizing atmosphere
d) Hydrogen-rich atmosphere
Answer: c) Oxidizing atmosphere
Explanation: Free oxygen produced by photosynthesis made Earth’s atmosphere oxidizing.
8. The “Iron Catastrophe” refers to—
a) The loss of iron to space
b) Differentiation of Earth’s core
c) Cooling of iron-rich crust
d) Formation of magnetosphere
Answer: b) Differentiation of Earth’s core
Explanation: During Earth’s early history, molten iron sank to form the core, creating magnetic protection.
9. The theory that Earth and other planets formed from planetesimals is called—
a) Planetesimal hypothesis
b) Capture hypothesis
c) Tidal hypothesis
d) Binary star hypothesis
Answer: a) Planetesimal hypothesis
Explanation: Proposed by Chamberlin and Moulton, it suggests planets formed from small solid bodies (planetesimals).
10. The age of the Earth is determined mainly by—
a) Fossil evidence
b) Radiometric dating
c) Carbon dating
d) Seismic activity
Answer: b) Radiometric dating
Explanation: Uranium-lead dating and other isotope methods give Earth’s age as 4.54 billion years.
11. The oldest known rocks on Earth are about—
a) 1.5 billion years old
b) 2.0 billion years old
c) 3.8–4.0 billion years old
d) 4.6 billion years old
Answer: c) 3.8–4.0 billion years old
Explanation: Rocks from Greenland, Canada, and Australia date back to ~3.8–4.0 Ga.
12. The origin of life on Earth is believed to have occurred about—
a) 2.5 billion years ago
b) 3.5–3.8 billion years ago
c) 1.5 billion years ago
d) 4.6 billion years ago
Answer: b) 3.5–3.8 billion years ago
Explanation: The earliest microfossils date to ~3.5 Ga, indicating life emerged soon after Earth cooled.
13. The Miller-Urey experiment tested—
a) Continental drift
b) Evolution of atmosphere
c) Origin of life from simple molecules
d) Radiometric dating
Answer: c) Origin of life from simple molecules
Explanation: Miller and Urey (1953) simulated early Earth conditions, producing amino acids.
14. The “Late Heavy Bombardment” period refers to—
a) Formation of the Himalayas
b) Intense meteorite impacts on Earth and Moon
c) Beginning of Ice Ages
d) Origin of life
Answer: b) Intense meteorite impacts on Earth and Moon
Explanation: Between 4.1–3.8 Ga, Earth experienced heavy asteroid impacts.
15. The Moon is believed to have formed from—
a) Capture theory
b) Giant impact hypothesis
c) Co-accretion theory
d) Fission theory
Answer: b) Giant impact hypothesis
Explanation: A Mars-sized body (Theia) collided with Earth, ejecting material that formed the Moon.
16. Which eon is called the “Age of Microbes”?
a) Archean
b) Proterozoic
c) Phanerozoic
d) Hadean
Answer: a) Archean
Explanation: Archean (4.0–2.5 Ga) saw the first stable crust and microbial life.
17. The Hadean Eon represents—
a) First multicellular life
b) Earth’s initial formation and crust development
c) Ice Age period
d) Formation of Pangaea
Answer: b) Earth’s initial formation and crust development
Explanation: Hadean (4.6–4.0 Ga) marks early Earth formation, no stable life forms.
18. The Great Oxidation Event occurred around—
a) 4.6 Ga
b) 2.4 Ga
c) 1.2 Ga
d) 600 Ma
Answer: b) 2.4 Ga
Explanation: Cyanobacteria released oxygen, changing atmosphere composition.
19. Which gas was absent in Earth’s early atmosphere?
a) CO₂
b) Oxygen
c) Methane
d) Ammonia
Answer: b) Oxygen
Explanation: Free oxygen was absent initially; it accumulated only after photosynthesis.
20. The Proterozoic Eon is significant because—
a) Earth was molten
b) First multicellular organisms appeared
c) First continents formed
d) Dinosaurs evolved
Answer: b) First multicellular organisms appeared
Explanation: Proterozoic (2.5 Ga–541 Ma) saw eukaryotes and multicellular life.
21. Which supercontinent formed around 335 million years ago?
a) Gondwana
b) Laurasia
c) Rodinia
d) Pangaea
Answer: d) Pangaea
Explanation: Pangaea was a supercontinent that later split into Gondwana and Laurasia.
22. The present continents began to drift apart about—
a) 335 Ma
b) 200 Ma
c) 65 Ma
d) 2.5 Ga
Answer: b) 200 Ma
Explanation: Pangaea started breaking apart during the Mesozoic (~200 Ma).
23. Which eon is known as the “visible life” eon?
a) Archean
b) Proterozoic
c) Phanerozoic
d) Hadean
Answer: c) Phanerozoic
Explanation: Phanerozoic (541 Ma–present) marks abundant fossils and visible life.
24. Which process led to the formation of Earth’s layered structure (core, mantle, crust)?
a) Plate tectonics
b) Differentiation
c) Accretion of planetesimals
d) Seafloor spreading
Answer: b) Differentiation
Explanation: Heavy elements sank to form the core, lighter ones formed mantle and crust.
25. The “Snowball Earth” hypothesis suggests—
a) Earth was once entirely molten
b) Earth was completely frozen at times
c) Earth had no oxygen
d) Earth had giant oceans only
Answer: b) Earth was completely frozen at times
Explanation: Evidence suggests global glaciations occurred ~700 Ma during the Proterozoic.
26. The age of the Moon is approximately—
a) 2 billion years
b) 3.5 billion years
c) 4.5 billion years
d) 5.5 billion years
Answer: c) 4.5 billion years
Explanation: The Moon formed soon after Earth, about 4.5 Ga ago, as per the giant impact hypothesis.
27. Which period is called the “Age of Dinosaurs”?
a) Paleozoic
b) Mesozoic
c) Cenozoic
d) Proterozoic
Answer: b) Mesozoic
Explanation: The Mesozoic Era (252–66 Ma) saw the dominance of dinosaurs.
28. The oldest microfossils on Earth are about—
a) 500 million years old
b) 1.2 billion years old
c) 3.5 billion years old
d) 4.6 billion years old
Answer: c) 3.5 billion years old
Explanation: Fossils of cyanobacteria (stromatolites) date back ~3.5 Ga.
29. Which event marked the end of the Mesozoic Era?
a) Formation of Himalayas
b) Mass extinction of dinosaurs
c) First human evolution
d) First land plants
Answer: b) Mass extinction of dinosaurs
Explanation: A mass extinction ~66 Ma (likely asteroid impact + volcanism) ended the Mesozoic.
30. The earliest supercontinent is known as—
a) Gondwana
b) Rodinia
c) Pangaea
d) Columbia
Answer: d) Columbia
Explanation: Columbia (1.8–1.5 Ga) is believed to be one of the earliest supercontinents.
31. The ocean that existed around Pangaea was—
a) Panthalassa
b) Tethys
c) Iapetus
d) Paleo-Atlantic
Answer: a) Panthalassa
Explanation: Panthalassa was the global ocean surrounding Pangaea.
32. The Tethys Sea existed between—
a) Africa and South America
b) Laurasia and Gondwana
c) Europe and Asia
d) North America and Europe
Answer: b) Laurasia and Gondwana
Explanation: The Tethys Sea separated northern Laurasia from southern Gondwana before India collided with Asia.
33. The Himalayas began to form around—
a) 200 million years ago
b) 100 million years ago
c) 50 million years ago
d) 10 million years ago
Answer: c) 50 million years ago
Explanation: The Himalayas formed after India collided with Eurasia ~50 Ma ago.
34. The Cenozoic Era is also called—
a) Age of Mammals
b) Age of Fishes
c) Age of Reptiles
d) Age of Amphibians
Answer: a) Age of Mammals
Explanation: After dinosaurs went extinct, mammals diversified during the Cenozoic (66 Ma–present).
35. Which gas was primarily responsible for early greenhouse warming of Earth?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Argon
Answer: b) Carbon dioxide
Explanation: Volcanic CO₂ in the early atmosphere kept Earth warm despite a fainter Sun.
36. What are stromatolites?
a) Igneous rocks
b) Fossilized microbial mats
c) Layers of ice
d) Volcanic deposits
Answer: b) Fossilized microbial mats
Explanation: Stromatolites are layered structures formed by cyanobacteria, oldest evidence of life.
37. Which eon witnessed the first appearance of animals with hard shells?
a) Archean
b) Proterozoic
c) Phanerozoic
d) Hadean
Answer: c) Phanerozoic
Explanation: The Cambrian Explosion (~541 Ma) in the Phanerozoic Eon marked rapid diversification of shelled animals.
38. The earliest continents are referred to as—
a) Cratons
b) Gondwana
c) Shields
d) Islands
Answer: a) Cratons
Explanation: Cratons are ancient stable parts of Earth’s lithosphere formed during the Archean.
39. The Carboniferous period is known for—
a) Abundance of dinosaurs
b) Formation of coal deposits
c) First appearance of humans
d) Origin of mammals
Answer: b) Formation of coal deposits
Explanation: Carboniferous (359–299 Ma) saw vast swamp forests that produced coal beds.
40. Which event marks the boundary between the Paleozoic and Mesozoic Eras?
a) Cambrian Explosion
b) End-Permian mass extinction
c) Great Oxidation Event
d) Ice Age
Answer: b) End-Permian mass extinction
Explanation: ~252 Ma, the largest mass extinction wiped out 90% of marine species.
41. Which supercontinent existed before Pangaea?
a) Gondwana
b) Rodinia
c) Columbia
d) Panthalassa
Answer: b) Rodinia
Explanation: Rodinia existed ~1.3–0.9 Ga before breaking apart.
42. The Quaternary Period is marked by—
a) Formation of Himalayas
b) Ice Ages and evolution of humans
c) Age of reptiles
d) Age of coal forests
Answer: b) Ice Ages and evolution of humans
Explanation: The Quaternary (2.58 Ma–present) includes repeated Ice Ages and rise of Homo sapiens.
43. Which process continues to modify Earth’s surface today?
a) Planetary accretion
b) Plate tectonics
c) Differentiation
d) Formation of atmosphere
Answer: b) Plate tectonics
Explanation: Plate movements reshape continents and ocean basins even today.
44. Which era is known as the “Age of Amphibians”?
a) Paleozoic
b) Mesozoic
c) Cenozoic
d) Proterozoic
Answer: a) Paleozoic
Explanation: Amphibians dominated the Carboniferous and Permian periods of the Paleozoic.
45. Which mineral is often used for radiometric dating to determine Earth’s age?
a) Quartz
b) Feldspar
c) Zircon
d) Calcite
Answer: c) Zircon
Explanation: Zircon crystals retain uranium and lead isotopes, useful for dating very old rocks.
46. The breakup of Gondwana began in which period?
a) Jurassic
b) Triassic
c) Cretaceous
d) Devonian
Answer: a) Jurassic
Explanation: Gondwana began breaking apart in the Jurassic (~180 Ma).
47. Which event led to the dominance of oxygen in Earth’s atmosphere?
a) Iron Catastrophe
b) Great Oxidation Event
c) Cambrian Explosion
d) Late Heavy Bombardment
Answer: b) Great Oxidation Event
Explanation: Around 2.4 Ga, photosynthetic bacteria increased oxygen levels dramatically.
48. Which is the most recent epoch of Earth’s history?
a) Miocene
b) Holocene
c) Pleistocene
d) Oligocene
Answer: b) Holocene
Explanation: Holocene (11,700 years–present) is the current epoch following the last Ice Age.
49. Which period is called the “Age of Fishes”?
a) Devonian
b) Silurian
c) Cambrian
d) Ordovician
Answer: a) Devonian
Explanation: Devonian (419–359 Ma) saw major diversification of fishes.
50. Which event marks the beginning of the Phanerozoic Eon?
a) Formation of Pangaea
b) Cambrian Explosion
c) Ice Age
d) First land plants
Answer: b) Cambrian Explosion
Explanation: Around 541 Ma, the Cambrian Explosion introduced diverse, complex life forms.
51. The Earth’s interior heat mainly comes from—
a) Solar radiation
b) Radioactive decay
c) Tidal forces
d) Lightning
Answer: b) Radioactive decay
Explanation: Heat is generated by the decay of isotopes like uranium, thorium, and potassium in Earth’s interior.
52. Which period is known as the “Age of Reptiles”?
a) Paleozoic
b) Mesozoic
c) Cenozoic
d) Quaternary
Answer: b) Mesozoic
Explanation: Reptiles, especially dinosaurs, dominated during the Mesozoic Era.
53. Which is considered the first true supercontinent?
a) Rodinia
b) Columbia
c) Pangaea
d) Gondwana
Answer: b) Columbia
Explanation: Columbia (Nuna) formed ~1.8 Ga, one of Earth’s earliest supercontinents.
54. Which event is associated with the sudden diversification of life 541 million years ago?
a) Great Oxidation Event
b) Cambrian Explosion
c) Snowball Earth
d) Pangaea formation
Answer: b) Cambrian Explosion
Explanation: The Cambrian Explosion marked rapid diversification of complex life in oceans.
55. Which group of organisms were the first oxygen producers on Earth?
a) Algae
b) Cyanobacteria
c) Fungi
d) Protozoa
Answer: b) Cyanobacteria
Explanation: Cyanobacteria carried out photosynthesis, releasing oxygen into the atmosphere.
56. The Chicxulub crater in Mexico is linked to—
a) Origin of the Moon
b) Great Oxidation Event
c) Dinosaur extinction
d) Pangaea breakup
Answer: c) Dinosaur extinction
Explanation: An asteroid impact ~66 Ma caused the Chicxulub crater, contributing to dinosaur extinction.
57. Which eon has the longest duration in Earth’s history?
a) Archean
b) Hadean
c) Proterozoic
d) Phanerozoic
Answer: c) Proterozoic
Explanation: The Proterozoic lasted ~2 billion years (2.5 Ga–541 Ma), the longest eon.
58. Which period is called the “Age of Coal”?
a) Silurian
b) Carboniferous
c) Jurassic
d) Triassic
Answer: b) Carboniferous
Explanation: Dense forests in the Carboniferous (359–299 Ma) created vast coal deposits.
59. The term “Ga” used in geology means—
a) Giant age
b) Gaseous atmosphere
c) Billion years ago
d) Global anomaly
Answer: c) Billion years ago
Explanation: Ga = Giga-annum = Billion years ago (10⁹ years).
60. The first land plants appeared during—
a) Cambrian
b) Silurian
c) Devonian
d) Carboniferous
Answer: b) Silurian
Explanation: Simple vascular plants colonized land in the Silurian (~430 Ma).
61. The first vertebrates appeared during—
a) Ordovician
b) Cambrian
c) Devonian
d) Triassic
Answer: b) Cambrian
Explanation: Primitive jawless fish appeared during the Cambrian Period.
62. The Permian-Triassic extinction wiped out about—
a) 30% of species
b) 50% of species
c) 70% of species
d) 90% of species
Answer: d) 90% of species
Explanation: The “Great Dying” ~252 Ma caused the largest known extinction, ~90% marine species lost.
63. The Cretaceous period ended about—
a) 65 million years ago
b) 100 million years ago
c) 200 million years ago
d) 300 million years ago
Answer: a) 65 million years ago
Explanation: The Cretaceous (145–66 Ma) ended with the extinction of dinosaurs.
64. The earliest humans (genus Homo) appeared around—
a) 2.5 million years ago
b) 1 million years ago
c) 500,000 years ago
d) 10,000 years ago
Answer: a) 2.5 million years ago
Explanation: Homo habilis appeared ~2.5 Ma, marking the beginning of human evolution.
65. Which eon directly followed the Hadean?
a) Archean
b) Proterozoic
c) Phanerozoic
d) Mesozoic
Answer: a) Archean
Explanation: Archean Eon (4.0–2.5 Ga) followed the Hadean, with stable crust and first life.
66. The term “Precambrian” refers to—
a) Time before Earth’s formation
b) Time before Cambrian Period
c) Age of Dinosaurs
d) Recent Ice Age
Answer: b) Time before Cambrian Period
Explanation: Precambrian includes Hadean, Archean, and Proterozoic Eons (88% of Earth’s history).
67. The first multicellular animals appeared during—
a) Proterozoic Eon
b) Archean Eon
c) Hadean Eon
d) Phanerozoic Eon
Answer: a) Proterozoic Eon
Explanation: Fossils of simple multicellular organisms date back ~1.6–1.2 Ga.
68. Which period is called the “Age of Amphibians”?
a) Devonian
b) Carboniferous
c) Permian
d) Jurassic
Answer: b) Carboniferous
Explanation: Amphibians flourished during the Carboniferous Period (359–299 Ma).
69. Which mass extinction wiped out the dinosaurs?
a) Ordovician extinction
b) Permian extinction
c) Cretaceous-Paleogene extinction
d) Devonian extinction
Answer: c) Cretaceous-Paleogene extinction
Explanation: ~66 Ma, asteroid impact + volcanism led to dinosaur extinction.
70. The oldest minerals found on Earth are—
a) Feldspar
b) Zircons
c) Quartz
d) Calcite
Answer: b) Zircons
Explanation: Zircons from Australia are 4.4 billion years old, oldest known minerals.
71. The first Ice Age occurred during which era?
a) Archean
b) Proterozoic
c) Paleozoic
d) Mesozoic
Answer: b) Proterozoic
Explanation: Evidence of glaciation exists from ~2.4 Ga in the Proterozoic Eon.
72. The Indian subcontinent separated from Gondwana around—
a) 300 Ma
b) 180 Ma
c) 100 Ma
d) 50 Ma
Answer: c) 100 Ma
Explanation: India drifted north after separating from Gondwana ~100 Ma ago.
73. Which event is associated with the rapid rise of oxygen levels in the oceans and atmosphere?
a) Cambrian Explosion
b) Great Oxidation Event
c) Snowball Earth
d) End-Cretaceous extinction
Answer: b) Great Oxidation Event
Explanation: Occurred ~2.4 Ga due to cyanobacteria photosynthesis.
74. The Jurassic Period is famous for—
a) First humans
b) Abundance of dinosaurs
c) Rise of mammals
d) Formation of Pangaea
Answer: b) Abundance of dinosaurs
Explanation: Jurassic (201–145 Ma) was the peak age of dinosaurs.
75. Which epoch is also called the “Ice Age epoch”?
a) Miocene
b) Holocene
c) Pleistocene
d) Oligocene
Answer: c) Pleistocene
Explanation: Pleistocene (2.58 Ma–11,700 years ago) had repeated glaciations.
76. The earliest known continent-sized landmass was—
a) Pangaea
b) Rodinia
c) Vaalbara
d) Gondwana
Answer: c) Vaalbara
Explanation: Vaalbara (3.1–2.8 Ga) is considered Earth’s earliest supercontinent.
77. Which event allowed complex animals to colonize land?
a) Cambrian Explosion
b) Oxygen accumulation in atmosphere
c) Formation of Pangaea
d) Carboniferous forests
Answer: b) Oxygen accumulation in atmosphere
Explanation: The rise of oxygen allowed development of ozone layer, protecting life from UV radiation.
78. Which period is known as the “Golden Age of Sharks”?
a) Devonian
b) Carboniferous
c) Jurassic
d) Triassic
Answer: b) Carboniferous
Explanation: Sharks diversified greatly during the Carboniferous Period.
79. The boundary between Paleozoic and Mesozoic eras is marked by—
a) End-Cretaceous extinction
b) End-Permian extinction
c) Cambrian Explosion
d) Great Oxidation Event
Answer: b) End-Permian extinction
Explanation: ~252 Ma, the largest mass extinction ended the Paleozoic Era.
80. The Ediacaran Period is known for—
a) First complex multicellular life
b) First dinosaurs
c) Formation of Himalayas
d) First humans
Answer: a) First complex multicellular life
Explanation: Ediacaran (635–541 Ma) marks the rise of soft-bodied multicellular organisms.
81. Which theory explains the movement of continents?
a) Plate tectonics
b) Accretion theory
c) Iron Catastrophe
d) Catastrophic hypothesis
Answer: a) Plate tectonics
Explanation: Plate tectonics explains drift, collision, and breakup of continents.
82. The term “Anthropocene” is used to describe—
a) Earliest Ice Age
b) Human-dominated epoch
c) Age of dinosaurs
d) Precambrian life
Answer: b) Human-dominated epoch
Explanation: Anthropocene is an unofficial term for the present era influenced by human activity.
83. Which period saw the first birds?
a) Devonian
b) Jurassic
c) Triassic
d) Cretaceous
Answer: b) Jurassic
Explanation: Archaeopteryx, the first bird, appeared in the Late Jurassic (~150 Ma).
84. The breakup of Rodinia led to the formation of—
a) Gondwana and Laurasia
b) Pannotia
c) Pangaea
d) Columbia
Answer: b) Pannotia
Explanation: Rodinia broke up ~750 Ma, forming a short-lived supercontinent called Pannotia.
85. Which group dominated the Cambrian seas?
a) Mammals
b) Trilobites
c) Dinosaurs
d) Amphibians
Answer: b) Trilobites
Explanation: Trilobites were the most abundant early marine arthropods during the Cambrian.
86. Which extinction event is considered the second largest after the Permian?
a) Cretaceous-Paleogene
b) Ordovician-Silurian
c) Devonian
d) Triassic-Jurassic
Answer: b) Ordovician-Silurian
Explanation: ~85% of marine species were lost ~444 Ma due to glaciation and sea-level fall.
87. The Cambrian Period began around—
a) 650 Ma
b) 541 Ma
c) 350 Ma
d) 250 Ma
Answer: b) 541 Ma
Explanation: The Cambrian marks the start of the Phanerozoic Eon.
88. Which event marks the start of the Quaternary Period?
a) Rise of dinosaurs
b) First hominids
c) Beginning of Ice Ages
d) Breakup of Pangaea
Answer: c) Beginning of Ice Ages
Explanation: Quaternary (2.58 Ma–present) began with repeated glaciations.
89. Which era is known as the “Age of Invertebrates”?
a) Paleozoic
b) Mesozoic
c) Cenozoic
d) Proterozoic
Answer: a) Paleozoic
Explanation: Early Paleozoic was dominated by invertebrate marine life.
90. The end of the Triassic period was marked by—
a) Rise of mammals
b) Extinction of many reptiles
c) Ice Age
d) Appearance of birds
Answer: b) Extinction of many reptiles
Explanation: A mass extinction ~201 Ma cleared ecological niches for dinosaurs to dominate.
91. The first mammals appeared during—
a) Carboniferous
b) Triassic
c) Jurassic
d) Cretaceous
Answer: b) Triassic
Explanation: Small, shrew-like mammals appeared in the Late Triassic (~225 Ma).
92. The largest animals ever to live on Earth are—
a) Dinosaurs
b) Blue Whales
c) Mammoths
d) Megalodons
Answer: b) Blue Whales
Explanation: The modern Blue Whale exceeds even the largest dinosaurs in mass.
93. Which period saw the first flowering plants (angiosperms)?
a) Jurassic
b) Cretaceous
c) Devonian
d) Silurian
Answer: b) Cretaceous
Explanation: Angiosperms evolved and diversified during the Cretaceous (~130 Ma).
94. The oldest known evidence of life is found in—
a) Granite
b) Stromatolites
c) Basalt
d) Coal
Answer: b) Stromatolites
Explanation: Stromatolites, formed by cyanobacteria, date back ~3.5 billion years.
95. The Paleozoic Era lasted from—
a) 600–250 Ma
b) 541–252 Ma
c) 450–200 Ma
d) 350–65 Ma
Answer: b) 541–252 Ma
Explanation: Paleozoic lasted ~289 million years, ending with the Permian extinction.
96. The first land vertebrates appeared in which period?
a) Devonian
b) Carboniferous
c) Silurian
d) Triassic
Answer: a) Devonian
Explanation: Devonian (~370 Ma) saw fish evolve into the first amphibians.
97. Which was the dominant life form during the Precambrian?
a) Dinosaurs
b) Microorganisms
c) Mammals
d) Amphibians
Answer: b) Microorganisms
Explanation: Bacteria and algae dominated the Precambrian Eons.
98. The breakup of Pangaea began in which era?
a) Paleozoic
b) Mesozoic
c) Cenozoic
d) Archean
Answer: b) Mesozoic
Explanation: Pangaea started breaking apart in the Mesozoic (~200 Ma).
99. The Holocene Epoch began—
a) 1 million years ago
b) 117,000 years ago
c) 11,700 years ago
d) 2,500 years ago
Answer: c) 11,700 years ago
Explanation: Holocene began after the last Ice Age ended.
100. The current geological time period is—
a) Holocene Epoch of Quaternary Period
b) Jurassic Period
c) Devonian Period
d) Carboniferous Period
Answer: a) Holocene Epoch of Quaternary Period
Explanation: We live in the Holocene Epoch (last 11,700 years) of the Quaternary Period.