Free Human Body and Health MCQs with Answers

471. Which of the following is not a mammal?

• A. Fish
• B. Cow
• C. Goat
• D. Whale

Explanation: Fish are not mammals because they generally breathe through gills, lay eggs and are cold-blooded. Cows, goats and whales are mammals, although whales live in water.

472. Which is the hardest substance in the human body?

• A. Tooth enamel
• B. Skull
• C. Knee cap
• D. Rib

Explanation: Tooth enamel is the hardest substance in the human body because it contains a very high proportion of mineral crystals. Bone is strong but is less hard and more flexible than enamel.

473. In the treatment of which disease is dialysis used?

• A. Ulcers
• B. Heart failure
• C. Kidney failure
• D. Brain tumour

Explanation: Dialysis replaces important kidney functions by removing wastes and excess fluid from the blood when the kidneys fail. It is not a treatment for ulcers, heart failure or brain tumours.

474. What causes mumps?

• A. Fungus
• B. Bacterium
• C. Deficiency of vitamins
• D. Virus

Explanation: Mumps is caused by the mumps virus, which commonly produces painful swelling of the salivary glands near the jaw. It is therefore not caused by bacteria, fungi or vitamin deficiency.

475. How many pairs of walking legs does a cockroach have?

• A. One
• B. Two
• C. Three
• D. Four

Explanation: A cockroach has three pairs of walking legs, one pair attached to each of its three thoracic segments. Its legs are jointed appendages characteristic of insects.

476. Which of the following is caused by a deficiency of iron in the diet?

• A. Giotre
• B. Scurvy
• C. Anaemia
• D. Rickets

Explanation: Iron is needed to make haemoglobin, the oxygen-carrying pigment in red blood cells, so deficiency commonly causes anaemia. Scurvy results from vitamin C deficiency, while rickets is linked mainly to vitamin D deficiency.

477. Which of the following animals does not have nervous system?

• A. Bat
• B. Squirrel
• C. Sponges
• D. Lizard

Explanation: Sponges have no nervous system or true nerve cells and respond through simple cellular mechanisms. Bats, squirrels and lizards are vertebrates with nervous systems.

478. Through which organ does a fish respire?

• A. Nose
• B. Lungs
• C. Gills
• D. Fins

Explanation: Fish respire through gills, whose thin surfaces extract dissolved oxygen from water and release carbon dioxide. Fins provide movement and balance rather than respiration.

479. Who first discovered how blood circulates in the human body?

• A. Edward Jenner
• B. Joseph Lister
• C. William Harvey
• D. Gregor Mendel

Explanation: William Harvey described the circulation of blood through the heart and blood vessels in the seventeenth century. Jenner is associated with vaccination, Lister with antiseptic surgery, and Mendel with genetics.

480. Inside which organ is the gallbladder located?

• A. Pancreas
• B. Liver
• C. Kidney
• D. Small intestine

Explanation: The gallbladder is a small sac attached to the underside of the liver, where it stores and concentrates bile made by the liver. It is not part of the kidney, pancreas or small intestine.