{"id":12881,"date":"2025-09-24T10:25:21","date_gmt":"2025-09-24T09:25:21","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12881"},"modified":"2026-01-13T08:01:24","modified_gmt":"2026-01-13T08:01:24","slug":"human-circulatory-system-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/24\/human-circulatory-system-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Human circulatory system 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 human circulatory system is also known as the<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">___________.<\/mark><\/strong><\/mark><\/mark><\/strong><br>A) Nervous system<br>B) Respiratory system<br>C) Cardiovascular system<br>D) Digestive system<\/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 circulatory system consists of the heart, blood, and blood vessels, collectively called the cardiovascular system.\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. What is the average volume of blood in an adult human?<\/mark><\/strong><br>A) 1\u20132 liters<br>B) 3\u20134 liters<br>C) 4\u20136 liters<br>D) 8\u201310 liters<\/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>  A healthy adult has about 4\u20136 liters of blood, depending on sex, age, and body size.\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. What is the normal pH of human blood?<\/mark><\/strong><br>A) 6.8<br>B) 7.0<br>C) 7.4<br>D) 8.0<\/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>  Blood is slightly alkaline with a normal pH of about 7.35\u20137.45.\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. Which component of blood is responsible for oxygen transport?<br><\/mark><\/strong>A) Platelets<br>B) Plasma<br>C) White blood cells<br>D) Red blood cells<\/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>  RBCs contain hemoglobin, which binds to oxygen for transport.\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. Hemoglobin is a<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">___________.<\/mark><\/strong><\/mark><br><\/mark><\/strong>A) Protein<br>B) Fat<br>C) Carbohydrate<br>D) Vitamin<\/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>  Hemoglobin is a conjugated protein with iron, responsible for carrying oxygen.\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 average lifespan of human red blood cells is<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">___________.<\/mark><\/strong><\/mark><\/mark><br><\/strong>A) 60 days<br>B) 90 days<br>C) 120 days<br>D) 150 days<\/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>   RBCs live for about 120 days before being broken down in the spleen.\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. Which blood cells are called \u201csoldiers of the body\u201d?<br><\/mark><\/strong>A) RBCs<br>B) WBCs<br>C) Platelets<br>D) Plasma<\/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>  WBCs protect the body against infections and foreign substances.\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. Which cells are responsible for blood clotting?<br><\/mark><\/strong>A) RBCs<br>B) WBCs<br>C) Platelets<br>D) Neutrophils<\/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>  Platelets release clotting factors that help in blood coagulation.\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. What is the liquid portion of blood called?<\/mark><\/strong><br>A) Serum<br>B) Plasma<br>C) Cytoplasm<br>D) Lymph<\/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>  Plasma is the straw-colored liquid that transports nutrients, hormones, and waste.\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. Which vitamin is essential for blood clotting?<br><\/mark><\/strong>A) Vitamin A<br>B) Vitamin B12<br>C) Vitamin C<br>D) Vitamin K<\/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>   Vitamin K is necessary for the synthesis of prothrombin, a clotting factor.\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. Which organ is called the \u201cgraveyard of RBCs\u201d?<\/mark><\/strong><br>A) Liver<br>B) Kidney<br>C) Spleen<br>D) Lungs<\/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 spleen destroys old and damaged RBCs.\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. Which type of WBC is most abundant in human blood?<br><\/mark><\/strong>A) Basophils<br>B) Eosinophils<br>C) Neutrophils<br>D) Lymphocytes<\/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>  Neutrophils form 60\u201370% of WBCs and fight bacterial infections.\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 blood group is called the universal donor?<br><\/mark><\/strong>A) A+<br>B) AB+<br>C) O\u2013<br>D) AB\u2013<\/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>  O\u2013 blood can be given to any group in emergencies, as it lacks A, B, and Rh antigens.\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. Which blood group is known as the universal recipient?<br><\/mark><\/strong>A) O+<br>B) A+<br>C) AB+<br>D) B+<\/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>  AB+ individuals can receive blood from any group due to the presence of all antigens.\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. The Rh factor is named after which animal?<br><\/mark><\/strong>A) Rabbit<br>B) Rat<br>C) Rhesus monkey<br>D) Rhinoceros<\/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>  Rh factor was first discovered in rhesus monkeys.\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. Which protein in plasma helps in defense?<br><\/mark><\/strong>A) Albumin<br>B) Globulin<br>C) Fibrinogen<br>D) Myosin<\/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>  Globulins act as antibodies in immune defense.\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. Which component helps maintain osmotic balance in blood?<br><\/mark><\/strong>A) Hemoglobin<br>B) Albumin<br>C) Globulin<br>D) Platelets<\/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>  Albumin regulates osmotic pressure and prevents fluid loss from blood vessels.\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. Which blood cells lack a nucleus in humans?<br><\/mark><\/strong>A) WBCs<br>B) RBCs<br>C) Platelets<br>D) Monocytes<\/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>  Mature RBCs lack nuclei to maximize oxygen-carrying space.\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 condition is caused by low hemoglobin?<br><\/mark><\/strong>A) Leukemia<br>B) Anemia<br>C) Hemophilia<br>D) Jaundice<\/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>  Anemia is due to insufficient RBCs or hemoglobin.\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 clotting factor is also called anti-hemophilic factor?<\/mark><\/strong><br>A) Factor I<br>B) Factor VIII<br>C) Factor IX<br>D) Factor X<\/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>  Deficiency of Factor VIII causes hemophilia A.\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. What is lymph?<br><\/mark><\/strong>A) Plasma without RBCs<br>B) Plasma without clotting factors<br>C) Tissue fluid in lymphatic vessels<br>D) Blood without platelets<\/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>  Lymph is colorless fluid that transports fats and immune cells.\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. What is the major function of lymph nodes?<br><\/mark><\/strong>A) Filter urine<br>B) Produce insulin<br>C) Trap pathogens<br>D) Digest fats<\/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>  Lymph nodes act as filters and activate immune responses.\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. Which metal is present in hemoglobin?<br><\/mark><\/strong>A) Magnesium<br>B) Iron<br>C) Copper<br>D) Zinc<\/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>  Each hemoglobin molecule has iron ions in heme groups that bind oxygen.\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. Which pigment gives red color to blood?<br><\/mark><\/strong>A) Chlorophyll<br>B) Hemocyanin<br>C) Hemoglobin<br>D) Bilirubin<\/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>  Hemoglobin gives red color due to its iron-porphyrin complex.\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. Which blood disorder is characterized by abnormal crescent-shaped RBCs?<br><\/mark><\/strong>A) Thalassemia<br>B) Leukemia<br>C) Sickle cell anemia<br>D) Hemophilia<\/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>  Caused by genetic mutation in hemoglobin, RBCs become sickle-shaped.\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. The human heart is located in the<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">___________.<\/mark><\/strong><\/mark><br><\/mark><\/strong>A) Abdominal cavity<br>B) Thoracic cavity<br>C) Cranial cavity<br>D) Pelvic cavity<\/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 heart lies in the thoracic cavity, between the lungs, slightly tilted to the left.\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 human heart is surrounded by a protective sac called<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">___________.<\/mark><\/strong><\/mark><br><\/mark><\/strong>A) Pleura<br>B) Pericardium<br>C) Peritoneum<br>D) Meninges<\/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 pericardium is a double-walled sac filled with pericardial fluid to reduce friction during heartbeats.\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. How many chambers are present in the human heart?<br><\/mark><\/strong>A) Two<br>B) Three<br>C) Four<br>D) Five<\/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 human heart has four chambers \u2013 two atria (upper) and two ventricles (lower).\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. Which chamber of the heart receives deoxygenated blood from the body?<br><\/mark><\/strong>A) Left atrium<br>B) Right atrium<br>C) Left ventricle<br>D) Right ventricle<\/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 right atrium receives deoxygenated blood from the superior and inferior vena cava.\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 chamber pumps oxygenated blood to the body?<br><\/mark><\/strong>A) Right atrium<br>B) Right ventricle<br>C) Left atrium<br>D) Left ventricle<\/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 left ventricle pumps oxygenated blood to the whole body via the aorta.\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 blood vessels carry blood from the heart to the lungs?<br><\/mark><\/strong>A) Pulmonary veins<br>B) Pulmonary arteries<br>C) Coronary arteries<br>D) Aorta<\/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>  Pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs.\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 blood vessels bring oxygenated blood from the lungs to the heart?<br><\/mark><\/strong>A) Pulmonary veins<br>B) Pulmonary arteries<br>C) Coronary veins<br>D) Vena cava<\/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>  Pulmonary veins carry oxygenated blood into the left atrium.\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. Which valve prevents backflow of blood from the right ventricle to the right atrium?<\/mark><\/strong><br>A) Bicuspid valve<br>B) Tricuspid valve<br>C) Semilunar valve<br>D) Aortic valve<\/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 tricuspid valve is located between the right atrium and right ventricle.\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 bicuspid valve is also called<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\">___________.<\/mark><\/strong><\/mark><\/mark><\/strong><br>A) Aortic valve<br>B) Mitral valve<br>C) Pulmonary valve<br>D) Coronary valve<\/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 bicuspid valve (mitral valve) is between the left atrium and left ventricle.\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. The largest artery in the human body is<mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><\/mark><br>A) Pulmonary artery<br>B) Carotid artery<br>C) Coronary artery<br>D) Aorta<\/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 aorta carries oxygen-rich blood from the left ventricle to the entire body.\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\">36. The contraction phase of the heart is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Diastole<br>B) Systole<br>C) Resting<br>D) Circulation<\/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>  During systole, the heart muscles contract and pump blood.\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\">37. The relaxation phase of the heart is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Systole<br>B) Diastole<br>C) Cardiac arrest<br>D) Conduction<\/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>  During diastole, the heart chambers relax and fill with blood.\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 sequence of events in one complete heartbeat is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Circulation<br>B) Cardiac cycle<br>C) Systole<br>D) Diastole<\/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>  One cardiac cycle includes systole and diastole of atria and ventricles.\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 average duration of a cardiac cycle in humans is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) 0.5 sec<br>B) 0.8 sec<br>C) 1.0 sec<br>D) 1.2 sec<\/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>  At an average heart rate of 75 beats per minute, one cycle lasts 0.8 seconds.\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. The pacemaker of the human heart is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) AV node<br>B) SA node<br>C) Bundle of His<br>D) Purkinje fibers<\/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 sinoatrial (SA) node initiates the heartbeat and is called the natural pacemaker.\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. Where is the SA node located?<\/mark><\/strong><br>A) Left atrium<br>B) Right atrium<br>C) Left ventricle<br>D) Right ventricle<\/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 SA node lies in the wall of the right atrium near the opening of the superior vena cava.\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 bundle of His is associated with<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) Hormone secretion<br>B) Heart conduction system<br>C) Oxygen transport<br>D) Blood clotting<\/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 bundle of His transmits impulses from the AV node to the ventricles.\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\">43. Which instrument is used to record electrical activity of the heart?<\/mark><\/strong><br>A) EEG<br>B) ECG<br>C) MRI<br>D) X-ray<\/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>  Electrocardiogram (ECG) records electrical impulses during heart activity.\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\">44. \u201cLub-dub\u201d heart sounds are produced 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) Blood circulation<br>B) Closing of valves<br>C) Expansion of atria<br>D) Contraction of muscles<\/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>  \u201cLub\u201d is closure of atrioventricular valves; \u201cdub\u201d is closure of semilunar valves.\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. Normal human heartbeat rate 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) 40\u201350 per minute<br>B) 60\u201380 per minute<br>C) 100\u2013120 per minute<br>D) 150\u2013200 per minute<\/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 adult heart rate is 72 beats per minute.\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\">46. Which hormone increases heart rate during stress or fear?<\/mark><\/strong><br>A) Insulin<br>B) Thyroxine<br>C) Adrenaline<br>D) Estrogen<\/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>  Adrenaline (epinephrine) stimulates faster heartbeat by acting on the SA node.\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 blood supply to the heart itself is provided 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) Aorta<br>B) Pulmonary artery<br>C) Coronary arteries<br>D) Jugular vein<\/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>  Coronary arteries branch from the aorta and supply oxygen to heart muscles.\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. In heart attack, which blood vessels are blocked?<\/mark><\/strong><br>A) Pulmonary arteries<br>B) Coronary arteries<br>C) Jugular veins<br>D) Carotid arteries<\/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>  Blockage of coronary arteries cuts off oxygen supply to heart muscles, causing myocardial infarction (heart attack).\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. Which condition refers to abnormal rhythm of heartbeat?<\/mark><\/strong><br>A) Tachycardia<br>B) Bradycardia<br>C) Arrhythmia<br>D) Hypertension<\/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>   Arrhythmia refers to irregular heartbeat due to electrical conduction problems.\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\">50. Artificial pacemakers are implanted in patients with malfunctioning<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) AV node<br>B) SA node<br>C) Both SA and AV node<br>D) Bundle of His<\/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>  Artificial pacemakers regulate heartbeats when the natural SA node fails.\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\">51. The type of blood circulation present in humans is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Single circulation<br>B) Double circulation<br>C) Open circulation<br>D) Mixed circulation<\/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>  Humans have double circulation \u2013 pulmonary (heart \u2192 lungs \u2192 heart) and systemic (heart \u2192 body \u2192 heart).\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\">52. Which scientist first described blood circulation in humans?<br><\/mark><\/strong>A) Aristotle<br>B) William Harvey<br>C) Hippocrates<br>D) Robert Hooke<\/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>  William Harvey (1628) discovered the circulation of blood and the role of the heart as a pump.\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. Blood circulation between heart and lungs is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Systemic circulation<br>B) Pulmonary circulation<br>C) Coronary circulation<br>D) Lymph circulation<\/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>  Pulmonary circulation carries deoxygenated blood to the lungs and oxygenated blood back to the heart.\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\">54. Blood circulation between heart and body organs (except lungs) is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Pulmonary circulation<br>B) Systemic circulation<br>C) Coronary circulation<br>D) Hepatic circulation<\/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>  Systemic circulation provides oxygenated blood to all body tissues.\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\">55. Which circulation supplies blood to the heart muscles themselves?<br><\/mark><\/strong>A) Pulmonary circulation<br>B) Systemic circulation<br>C) Coronary circulation<br>D) Portal circulation<\/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>  Coronary circulation ensures continuous oxygen and nutrients to heart tissues.\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\">56. What is the average blood pressure in humans?<br><\/mark><\/strong>A) 80\/60 mmHg<br>B) 120\/80 mmHg<br>C) 140\/100 mmHg<br>D) 160\/120 mmHg<\/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>  Normal blood pressure is systolic 120 mmHg and diastolic 80 mmHg.\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 instrument used to measure blood pressure is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) ECG<br>B) Spirometer<br>C) Sphygmomanometer<br>D) Hygrometer<\/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>  A sphygmomanometer measures systolic and diastolic blood pressure.\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\">58. High blood pressure is also called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Hypotension<br>B) Hypertension<br>C) Arrhythmia<br>D) Angina<\/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>  Hypertension is when blood pressure is persistently above normal, e.g., above 140\/90 mmHg.\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\">59. Low blood pressure is called<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Hypertension<br>B) Hypotension<br>C) Angina<br>D) Stroke<\/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>  Hypotension is abnormally low blood pressure, causing dizziness and fainting.\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\">60. Which of the following is not a blood vessel?<br><\/mark><\/strong>A) Artery<br>B) Vein<br>C) Capillary<br>D) Neuron<\/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>  Arteries, veins, and capillaries are blood vessels, while neurons are nerve cells.\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\">61. Which blood vessels carry blood away from the heart?<br><\/mark><\/strong>A) Veins<br>B) Arteries<br>C) Capillaries<br>D) Venules<\/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>  Arteries carry blood from the heart to body parts (usually oxygenated blood).\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\">62. Which blood vessels carry blood toward the heart?<br><\/mark><\/strong>A) Arteries<br>B) Veins<br>C) Capillaries<br>D) Arterioles<\/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>  Veins return blood to the heart (usually deoxygenated blood).\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 smallest blood vessels are<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Arteries<br>B) Veins<br>C) Capillaries<br>D) Venules<\/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>  Capillaries are one-cell thick and allow exchange of gases, nutrients, and wastes.\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. Which artery supplies blood to the brain?<br><\/mark><\/strong>A) Jugular artery<br>B) Carotid artery<br>C) Coronary artery<br>D) Pulmonary artery<\/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>  Carotid arteries deliver oxygenated blood to the brain.\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. Which vein carries oxygenated blood?<br><\/mark><\/strong>A) Pulmonary vein<br>B) Jugular vein<br>C) Coronary vein<br>D) Hepatic vein<\/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 pulmonary vein carries oxygenated blood from lungs to left atrium.\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 artery carries deoxygenated blood?<br><\/mark><\/strong>A) Aorta<br>B) Coronary artery<br>C) Pulmonary artery<br>D) Carotid artery<\/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>  Pulmonary arteries carry deoxygenated blood from right ventricle to lungs.\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 hepatic portal vein carries blood from<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Kidney to liver<br>B) Intestine to liver<br>C) Heart to brain<br>D) Lungs to heart<\/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 hepatic portal vein carries nutrient-rich blood from the intestine to the liver.\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 condition is caused by narrowing of coronary arteries?<\/mark><\/strong><br>A) Hypertension<br>B) Angina pectoris<br>C) Stroke<br>D) Anemia<\/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>  Angina occurs when blood supply to the heart muscle is reduced, causing chest pain.\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. A sudden blockage of blood flow to the brain causes<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) Hypertension<br>B) Stroke<br>C) Hemophilia<br>D) Anemia<\/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>  Stroke is caused by interruption of blood flow in brain arteries.\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 disease is known as \u201csilent killer\u201d?<\/mark><\/strong><br>A) Diabetes<br>B) Hypertension<br>C) Stroke<br>D) Tuberculosis<\/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>  Hypertension often shows no symptoms until severe damage occurs, hence called the silent killer.\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. Varicose veins are caused by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Bacterial infection<br>B) Weak valves in veins<br>C) High blood sugar<br>D) Lack of hemoglobin<\/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>  Faulty valves cause blood pooling, leading to twisted, enlarged veins.\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\">72. Atherosclerosis is caused by<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Parasite infection<br>B) Deposition of cholesterol in arteries<br>C) Deficiency of hemoglobin<br>D) Clotting factor deficiency<\/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>  Atherosclerosis narrows arteries due to fatty deposits (plaques).\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\">73. Hemophilia is a disease related to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) RBC deficiency<br>B) Platelet deficiency<br>C) Clotting factor deficiency<br>D) WBC deficiency<\/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>  Hemophilia is a genetic disorder where blood fails to clot properly.\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. Leukemia is also known as<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Blood cancer<br>B) Heart attack<br>C) Hypertension<br>D) Stroke<\/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>  Leukemia is uncontrolled proliferation of abnormal white blood cells.\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. Which organ regulates blood pressure by controlling blood volume?<br><\/mark><\/strong>A) Liver<br>B) Kidney<br>C) Spleen<br>D) Pancreas<\/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>  Kidneys regulate blood volume and pressure by controlling water and salt balance.\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 heartbeat originates due to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Nerve stimulation<br>B) Hormone secretion<br>C) Myogenic activity of heart muscles<br>D) Skeletal muscles<\/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 human heart is myogenic; impulses are generated in the SA node without external nerves.\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 \u201cheart of hearts\u201d (regulating heart rate) is<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) AV node<br>B) SA node<br>C) Purkinje fibers<br>D) Bundle of His<\/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 SA node initiates impulses that control heart rhythm.\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 blood vessel is used for pulse measurement at the wrist?<br><\/mark><\/strong>A) Carotid artery<br>B) Jugular vein<br>C) Radial artery<br>D) Ulnar vein<\/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>  Pulse is commonly measured by palpating the radial artery at the wrist.\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 artery is most commonly affected in a heart attack?<br><\/mark><\/strong>A) Carotid artery<br>B) Coronary artery<br>C) Radial artery<br>D) Pulmonary artery<\/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>  Blockage of coronary arteries reduces blood flow to heart muscles, causing myocardial infarction.\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. Which condition is characterized by prolonged high blood sugar damaging blood vessels?<br><\/mark><\/strong>A) Diabetes mellitus<br>B) Atherosclerosis<br>C) Hypertension<br>D) Anemia<\/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>  Diabetes damages blood vessels, increasing risk of circulatory diseases.\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. Which artery carries blood to the kidneys?<br><\/mark><\/strong>A) Coronary artery<br>B) Carotid artery<br>C) Renal artery<br>D) Hepatic artery<\/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>  Renal arteries supply blood directly to kidneys.\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>82. The term \u201ctachycardia\u201d refers to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><\/strong><\/mark><br>A) Slow heartbeat<br>B) Irregular heartbeat<br>C) Fast heartbeat<br>D) Absent heartbeat<\/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>  Tachycardia is a heart rate above 100 beats per minute.\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>83. The term \u201cbradycardia\u201d refers to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><\/strong><\/mark><br>A) Slow heartbeat<br>B) Fast heartbeat<br>C) Irregular heartbeat<br>D) Absent heartbeat<\/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>  Bradycardia is a heart rate below 60 beats per minute.\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 artery is palpated in the neck to check pulse?<br><\/mark><\/strong>A) Carotid artery<br>B) Jugular vein<br>C) Subclavian artery<br>D) Axillary artery<\/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>  Carotid arteries in the neck are used to check pulse, especially in emergencies.\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. What is the function of Purkinje fibers?<br><\/mark><\/strong>A) Supply oxygen to heart<br>B) Generate impulses in heart<br>C) Distribute impulses to ventricular walls<br>D) Close heart valves<\/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>  Purkinje fibers spread conduction signals for coordinated ventricular contraction.\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. Which blood disorder is linked with bone marrow cancer?<br><\/mark><\/strong>A) Anemia<br>B) Leukemia<br>C) Hemophilia<br>D) Thrombocytopenia<\/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>  Leukemia originates in bone marrow due to uncontrolled WBC production.\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 type of blood circulation is absent in fishes?<br><\/mark><\/strong>A) Single circulation<br>B) Double circulation<br>C) Closed circulation<br>D) Systemic circulation<\/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>  Fishes have single circulation; blood passes through heart only once in each circuit.\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. \u201cSilent heart attack\u201d often occurs in patients with<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Asthma<br>B) Diabetes<br>C) Tuberculosis<br>D) Malaria<\/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>  Diabetes damages nerves, reducing pain sensation during heart attacks.\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 blood pressure is highest in which blood vessels?<br><\/mark><\/strong>A) Veins<br>B) Capillaries<br>C) Arteries<br>D) Venules<\/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>  Arteries carry blood at high pressure directly pumped from the heart.\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. Which structure prevents backflow of blood inside veins?<br><\/mark><\/strong>A) Muscles<br>B) Valves<br>C) Capillaries<br>D) Nerves<\/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>  Veins contain valves that prevent blood from flowing backward.\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. Which organ produces erythropoietin, a hormone for RBC production?<br><\/mark><\/strong>A) Heart<br>B) Kidney<br>C) Liver<br>D) Spleen<\/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>   Kidneys secrete erythropoietin, which stimulates bone marrow to produce RBCs.\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. Normal cardiac output in a healthy adult is approximately<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) 1 liter\/min<br>B) 2 liters\/min<br>C) 5 liters\/min<br>D) 10 liters\/min<\/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>  Cardiac output = stroke volume \u00d7 heart rate; about 5 liters\/min in adults.\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. Stroke volume refers to<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Blood pumped per second<br>B) Blood pumped per beat<br>C) Blood pumped per minute<br>D) Blood pumped per hour<\/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>  Stroke volume is the amount of blood pumped by one ventricle in a single heartbeat.\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. In ECG, the QRS complex represents<strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-luminous-vivid-orange-color\"> ___________.<\/mark><\/strong><br><\/mark><\/strong>A) Atrial depolarization<br>B) Ventricular depolarization<br>C) Ventricular repolarization<br>D) Atrial repolarization<\/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>  QRS complex indicates depolarization of ventricles (leading to contraction).\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 vitamin deficiency causes anemia due to impaired RBC formation?<br><\/mark><\/strong>A) Vitamin A<br>B) Vitamin B12<br>C) Vitamin C<br>D) Vitamin D<\/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>  Vitamin B12 deficiency leads to pernicious anemia.\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 blood cells are involved in allergic reactions?<br><\/mark><\/strong>A) Neutrophils<br>B) Basophils<br>C) Monocytes<br>D) Lymphocytes<\/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>  Basophils release histamine, causing allergic responses.\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. \u201cAthlete\u2019s heart\u201d is a condition of ___________.<br><\/mark><\/strong>A) Weak heart muscles<br>B) Enlarged and strong heart due to exercise<br>C) Irregular heartbeat<br>D) Heart failure<\/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>  Regular exercise increases heart muscle mass, improving cardiac efficiency.\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 test detects blockage in coronary arteries?<br><\/mark><\/strong>A) EEG<br>B) ECG<br>C) Angiography<br>D) Spirometry<\/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>  Angiography uses dye and X-ray imaging to detect coronary blockages.\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. Which modern surgical technique replaces blocked coronary arteries?<br><\/mark><\/strong>A) Dialysis<br>B) Bypass surgery<br>C) Endoscopy<br>D) Biopsy<\/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>  Coronary bypass surgery restores blood flow by grafting alternate vessels.\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\">100. Which artificial device is used to maintain blood circulation during open-heart surgery?<\/mark><\/strong><br>A) Defibrillator<br>B) Heart\u2013lung machine<br>C) Dialysis machine<br>D) Pacemaker<\/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>  A heart\u2013lung machine temporarily takes over circulation and oxygenation during surgery.\n <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>1. The human circulatory system is also known as the___________.A) Nervous systemB) Respiratory systemC) Cardiovascular systemD) Digestive system Show Answer Answer: C Explanation: The circulatory system consists of the heart, blood, and blood vessels, collectively called the cardiovascular system. 2. What is the average volume of blood in an adult human?A) 1\u20132 litersB) 3\u20134 litersC)<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[16294,16151,16133,16155,16154,16147,16158,16139,16297,16296,16233,16232,16223,16228,16293,16298,16135,16227,16230,16235,16225,16299,16295,10990,4029,16156,5649,5623,16226,16134,16220,16132,16219,16140,16300],"class_list":{"0":"post-12881","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-biology","7":"tag-arteries","8":"tag-biology-learning","9":"tag-biology-mcqs","10":"tag-biology-preparation-material","11":"tag-biology-questions-and-answers","12":"tag-biology-quiz","13":"tag-biology-revision","14":"tag-biology-study-material","15":"tag-blood-components","16":"tag-blood-pressure","17":"tag-blood-vessels","18":"tag-capillaries","19":"tag-cardiac-cycle","20":"tag-chambers-of-heart","21":"tag-circulation-of-blood","22":"tag-circulatory-disorders","23":"tag-competitive-exam-biology","24":"tag-deoxygenated-blood","25":"tag-ecg-basics","26":"tag-heart-structure","27":"tag-heartbeat","28":"tag-human-circulation-problems","29":"tag-human-circulatory-system","30":"tag-human-circulatory-system-top-100-mcqs-with-answer-and-explanation","31":"tag-mcqs-adda","32":"tag-mcqs-for-biology-exam","33":"tag-mcqs-for-pc-psi-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","34":"tag-mcqs-for-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","35":"tag-oxygenated-blood","36":"tag-psc-biology-mcqs","37":"tag-pulmonary-circulation","38":"tag-ssc-biology-mcqs","39":"tag-systemic-circulation","40":"tag-upsc-biology-mcqs","41":"tag-veins"},"_links":{"self":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12881","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=12881"}],"version-history":[{"count":103,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12881\/revisions"}],"predecessor-version":[{"id":36330,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12881\/revisions\/36330"}],"wp:attachment":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/media?parent=12881"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/categories?post=12881"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/tags?post=12881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}