50. Complete the analogy: Blood : connective tissue :: Bone : ______.
[RRB Technician Grade III — 20 December 2024, Shift 3]
- (A) Muscular tissue
- (B) Epithelial tissue
- (C) Nervous tissue
- (D) Connective tissue
Answer: (D) Connective tissue
Explanation: Bone and blood both belong to the connective tissue family, although their matrices differ greatly. Bone has a mineralised solid matrix for support and protection, whereas blood has a fluid plasma matrix for transport. Muscle and nervous tissues have separate primary functions.
49. Deficiency of which vitamin may lead to prolonged bleeding from wounds?
[SSC MTS — 21 October 2024, Shift 1]
- (A) Vitamin E
- (B) Vitamin A
- (C) Vitamin B12
- (D) Vitamin K
Answer: (D) Vitamin K
Explanation: Vitamin K is required for activation of several coagulation proteins, including prothrombin and factors VII, IX and X. Deficiency impairs normal clot formation, sometimes producing abnormal bleeding. The vitamin is therefore important to the haemostatic function of the circulatory system.
48. Which agglutinogens occur on the red cells of a person with blood group O?
[RPSC RAS Prelims — 2023]
- (A) Both A and B
- (B) Only B
- (C) Neither A nor B
- (D) Only A
Answer: (C) Neither A nor B
Explanation: In the ABO classification, type O red cells possess neither A nor B antigen on their surfaces. Their plasma normally contains anti-A and anti-B antibodies. Rh status is a separate feature; therefore O positive and O negative are not interchangeable for every recipient.
47. Which of these medical-specialist pairings is incorrect?
[WBCS (Executive) Prelims — 2023]
- (A) Kidney diseases — urologist
- (B) Blood diseases — haematologist
- (C) Stomach diseases — gastroenterologist
- (D) Cancer — oncologist
Answer: (A) Kidney diseases — urologist
Explanation: A haematologist specialises in conditions involving blood and its forming tissues, including anaemia and leukaemia. Although urologists treat the urinary tract surgically, a nephrologist is the more specific physician for many medical kidney diseases; therefore that pairing is the incorrect one.
46. A sphygmomanometer is primarily used to measure what?
[SSC CGL — 14 July 2023, Memory-Based Paper]
- (A) Blood glucose
- (B) Blood pressure
- (C) Cholesterol
- (D) Uric acid
Answer: (B) Blood pressure
Explanation: A sphygmomanometer measures pressure exerted by flowing blood on arterial walls. Traditional readings are expressed as systolic over diastolic pressure, in millimetres of mercury. Blood glucose requires a glucometer, while cholesterol and uric acid are generally determined through laboratory blood analysis.
45. Which vessels carry blood from the heart to the different organs of the body?
[SSC MTS — 15 June 2023, Shift 1]
- (A) Veins
- (B) Tracheae
- (C) Arteries
- (D) Plasma
Answer: (C) Arteries
Explanation: Arteries carry blood away from the pumping heart. Their branches, the arterioles, feed capillary networks where exchange with tissues occurs. The pulmonary artery carries oxygen-poor blood, showing that direction of flow, not oxygen content, defines an artery.
44. Which vitamin helps blood clot normally in humans?
[MPPSC State Services Prelims 2022 — held 21 May 2023]
- (A) Vitamin A
- (B) Vitamin B
- (C) Vitamin K
- (D) Vitamin D
Answer: (C) Vitamin K
Explanation: Vitamin K supports activation of important coagulation factors through gamma-carboxylation in the liver. Without adequate vitamin K, the clotting cascade functions poorly and bleeding may persist. It also participates in the metabolism of proteins involved in maintaining healthy bone tissue.
43. In which component of human blood is the respiratory pigment haemoglobin present?
[RRB Group D — 11 October 2022, Shift 2]
- (A) White blood corpuscles
- (B) Red blood corpuscles
- (C) Blood platelets
- (D) Blood plasma
Answer: (B) Red blood corpuscles
Explanation: Haemoglobin is concentrated inside erythrocytes, or red blood corpuscles. Each molecule contains four haem groups capable of binding oxygen reversibly. This arrangement enables blood to transport much more oxygen than could dissolve in plasma alone, supporting aerobic respiration in tissues.
42. The pulmonary vein of the human heart opens into which chamber?
[RRB Group D — 6 October 2022, Shift 2]
- (A) Right atrium
- (B) Left ventricle
- (C) Left atrium
- (D) Right ventricle
Answer: (C) Left atrium
Explanation: Pulmonary veins return oxygenated blood from lung capillaries to the left atrium, also called the left auricle. Blood then flows through the mitral valve into the left ventricle. From there it enters the aorta and supplies the systemic circulation.
41. Which blood constituent provides immune protection against germs?
[RRB Group D — 6 October 2022, Shift 2]
- (A) White blood cells
- (B) Platelets
- (C) Plasma
- (D) Red blood cells
Answer: (A) White blood cells
Explanation: White blood cells collectively protect the body from invading microorganisms and other foreign substances. Phagocytic cells engulf many pathogens, while B and T lymphocytes support specific immune responses. In contrast, erythrocytes convey oxygen and platelets help plug damaged blood vessels.
