40. Match: I. Heart; II. Arteries; III. Veins
with A. Pumping organ; B. Carry deoxygenated blood; C. Carry oxygenated blood (usual systemic pattern).
[RRB Group D — 22 September 2022, Shift 1]
- (A) I–C, II–B, III–A
- (B) I–A, II–B, III–C
- (C) I–C, II–A, III–B
- (D) I–A, II–C, III–B
Answer: (D) I–A, II–C, III–B
Explanation: The heart functions as a muscular pump. In systemic circulation, arteries generally deliver oxygen-rich blood to tissues and veins return oxygen-poor blood to the heart. The pulmonary artery and pulmonary veins are major exceptions to this oxygenation pattern, but not to flow direction.
39. What carries most digested and absorbed fats away from the intestine?
[RRB Group D — 14 September 2022, Shift 3]
- (A) Plasma
- (B) Lymph
- (C) Platelets
- (D) Veins
Answer: (B) Lymph
Explanation: Intestinal lacteals, which are specialised lymphatic capillaries, absorb many dietary fats packaged as chylomicrons. The fat-rich lymph later enters the bloodstream through large lymphatic ducts. This route differs from many water-soluble nutrients, which enter the hepatic portal blood.
38. Which fluid transports dissolved food, carbon dioxide and nitrogenous wastes in blood?
[RRB Group D — 13 September 2022, Shift 1]
- (A) Plasma
- (B) White blood cells
- (C) Red blood cells
- (D) Platelets
Answer: (A) Plasma
Explanation: Plasma forms the liquid phase of blood, carrying soluble nutrients, electrolytes and waste materials. Urea travels through plasma towards the kidneys for removal. Most carbon dioxide travels as bicarbonate, with smaller amounts dissolved or bound to blood proteins, including haemoglobin.
37. Which statement about blood circulation in fish is FALSE?
[RRB Group D — 13 September 2022, Shift 1]
- (A) Ventricular blood flows towards the gills
- (B) Gills send oxygenated blood to the body
- (C) Blood from the body enters an atrium
- (D) A two-chambered heart produces double circulation
Answer: (D) A two-chambered heart produces double circulation
Explanation: Fish typically have a single circulatory circuit. Their two-chambered heart pumps oxygen-poor blood towards the gills, where it is oxygenated before travelling to body tissues. Blood then returns to the heart without passing through a separate pulmonary circuit as in mammals.
36. Which hormone raises the heartbeat in mammals during an emergency?
[UPSC NDA-II, General Ability Test — 4 September 2022]
- (A) Insulin
- (B) Melatonin
- (C) Thyroxine
- (D) Adrenaline
Answer: (D) Adrenaline
Explanation: Adrenaline, released by the adrenal medulla during stress, activates sympathetic responses. It raises heart rate and contractility and helps redirect blood flow towards actively responding tissues. This rapid fight-or-flight action differs from insulin’s glucose-lowering role or melatonin’s circadian regulation.
35. Which organism has a three-chambered heart?
[RRB Group D — 2 September 2022, Shift 2]
- (A) Bird
- (B) Frog
- (C) Fish
- (D) Human
Answer: (B) Frog
Explanation: Adult frogs possess two atria and one ventricle, giving a three-chambered heart. Fish generally have two main chambers, while birds and mammals have four. Amphibian circulation allows some mixing of oxygenated and deoxygenated blood within the single ventricle.
34. Which ABO blood group is traditionally known as the universal donor?
[RRB Group D — 30 August 2022, Shift 3]
- (A) A
- (B) B
- (C) AB
- (D) O
Answer: (D) O
Explanation: Within the ABO system, group O red cells lack both A and B surface antigens. When the Rh factor is also considered, O-negative red cells are the standard emergency universal donor type. Modern transfusion practice still requires careful compatibility testing whenever feasible.
33. Which statement about the circulatory system is incorrect?
[RRB Group D — 22 August 2022, Shift 3]
- (A) Hypertension results from constriction of veins
- (B) Platelets help clotting
- (C) Lymph is tissue fluid
- (D) Capillaries drain through vessels forming veins
Answer: (A) Hypertension results from constriction of veins
Explanation: Systemic arterial resistance is important in determining blood pressure; constriction of arteries and arterioles can increase it. Constriction of veins is not the standard explanation of hypertension. Platelets assist coagulation, and capillaries drain into venules that unite to form larger veins.
32. Which vitamin is involved in normal clotting of blood?
[WBCS (Executive) Prelims — 2022]
- (A) Vitamin A
- (B) Vitamin D
- (C) Vitamin B
- (D) Vitamin K
Answer: (D) Vitamin K
Explanation: Vitamin K is required to produce functionally active forms of several clotting proteins. When levels are inadequate, clot formation may be delayed and bleeding risk increases. Green leafy vegetables supply phylloquinone, one major dietary form of this fat-soluble vitamin.
31. The watery portion of blood containing salts and proteins is called ______.
[RRB NTPC CBT-II, Level 3 — 14 June 2022, Shift 1]
- (A) Platelets
- (B) Red blood cells
- (C) Plasma
- (D) White blood cells
Answer: (C) Plasma
Explanation: Plasma is the liquid portion of whole blood, consisting mostly of water together with salts, proteins, hormones and dissolved nutrients. It generally accounts for roughly fifty-five percent of total blood volume. Removing clotting factors from plasma produces serum, a related but distinct fluid.
