Important MCQs on Nervous System, Skeletal System, Muscles, Teeth & Biological Compounds for Competitive Exams (Part-III)

1. Structure and Composition

1. Which of the following is the hardest substance in the human body?
   (A) Bone
   (B) Enamel
   (C) Dentine
   (D) Nail
   ✅ Ans: (B)
2. The hardest part of the body is –
   (A) Bones
   (B) Tooth Enamel
   (C) Skull
   (D) Spinal Cord
   ✅ Ans: (B)
3. What does enamel cover?
   (A) Crown of the tooth
   (B) Dentin on all sides
   (C) Cementum
   (D) Cementum and partly dentin
   ✅ Ans: (A)
4. Our bones and teeth are generally made of –
   (A) Tricalcium phosphate
   (B) Fluorapatite
   (C) Chlorapatite
   (D) Hydrolith
   ✅ Ans: (A)
5. How many types of teeth are there in humans?
   (A) 4
   (B) 5
   (C) 2
   (D) 3
   ✅ Ans: (A)
6. An adult human normally has –
   (A) 6 molar teeth
   (B) 8 molar teeth
   (C) 10 molar teeth
   (D) 12 molar teeth
   ✅ Ans: (D)

2. Bone Count and Structure

7. The total number of bones in the human body is –
   (A) 206
   (B) 260
   (C) 306
   (D) 360
   ✅ Ans: (A)
8. The total number of vertebrae in a human being is –
   (A) 26
   (B) 30
   (C) 29
   (D) 33
   ✅ Ans: (D)
9. The total number of ear bones is –
   (A) 2
   (B) 4
   (C) 6
   (D) 8
   ✅ Ans: (C)

3. Bone Types and Locations

10. In a human body, the longest bone is in the –
    (A) Vertebral column
    (B) Thigh
    (C) Ribcage
    (D) Arm
    ✅ Ans: (B)
11. The strongest bone of the body is present in the –
    (A) Thigh
    (B) Jaw
    (C) Arm
    (D) Neck
    ✅ Ans: (A)
12. Bones are pneumatic in –
    (A) Fishes
    (B) Amphibians
    (C) Reptiles
    (D) Birds
    ✅ Ans: (D)

4. Joints and Connective Tissues

13. Which of these joints is a hinge joint?
    (A) Hip
    (B) Elbow
    (C) Shoulder
    (D) Wrist
    ✅ Ans: (B)
14. The connective tissue that connects a muscle to a bone is –
    (A) Cartilage
    (B) Ligament
    (C) Tendon
    (D) Interstitial fluid
    ✅ Ans: (C)

5. Skeletal Disorders and Deficiencies

15. The limb bones of children become bent if there is deficiency of vitamin –
    (A) A
    (B) B1
    (C) D
    (D) E
    ✅ Ans: (C)

🧠 Nervous System & Other Physiological Topics

1. Skin and Thermoregulation

16. Which of the following structure present in mammalian skin directly helps in keeping the body warm?
    (A) Pigmented Cells
    (B) Sweat Glands
    (C) Lymph Vessels
    (D) Blood Capillaries
    ✅ Ans: (D) (Blood vessels in skin help regulate heat via vasodilation and constriction. Sweat glands help cool the body, not warm it.)
17. Sweat glands in mammals are primarily concerned with –
    (A) Removal of excess salts
    (B) Excretion of nitrogenous wastes
    (C) Thermoregulation
    (D) Sex-attraction
    ✅ Ans: (C)

2. Invertebrate Biology

18. An invertebrate does not have –
    (A) Notochord
    (B) Body Cavity
    (C) Haemocoel
    (D) Gills
    ✅ Ans: (A)

3. Miscellaneous

19. Taenia solium (tapeworm) lives as a parasite in –
    (A) Pig
    (B) Abdomen of man/woman
    (C) Intestine of man/woman
    (D) Liver of man/woman
    ✅ Ans: (C) (Pigs are intermediate hosts. Humans are definitive hosts where adult worms live in the intestine.)
20. Of which tissue nails, hoofs and horns are made of?
    (A) Cuticle
    (B) Chitin
    (C) Keratin
    (D) Tunicin
    ✅ Ans: (C)