10th class Biology, Chapter 2: Human Respiratory System MCQs

1. Breathing means:

1. (A) Breakdown of C-H bonds to produce energy
2. (B) Movements that take air in and out of body ✓
3. (C) Getting oxygen from the air and removing carbon dioxide
4. (D) Transport of oxygen through blood to different parts of the body

2. Which path does air take immediately after passing through the larynx?

1. (A) Pharynx
2. (B) Bronchi
3. (C) Trachea ✓
4. (D) Alveoli

3. Why are alveoli surrounded by capillaries?

1. (A) To absorb water
2. (B) To exchange gases ✓
3. (C) To produce mucus
4. (D) To trap dust particles

4. Which feature of alveoli helps in rapid gas exchange?

1. (A) Thick walls
2. (B) Large diameter
3. (C) Moist surface ✓
4. (D) Strong muscles

5. Which action increases lung volume during breathing?

1. (A) Relaxing the diaphragm
2. (B) Contracting intercostal muscles ✓
3. (C) Closing the trachea
4. (D) Stiffening alveolar walls

6. Inhaled air contains 21% oxygen. What is its percentage in exhaled air?

1. (A) 0%
2. (B) 16% ✓
3. (C) 21%
4. (D) 42%

7. Which factor controls the breathing rate?

1. (A) Carbon dioxide in blood ✓
2. (B) Oxygen in blood
3. (C) Carbon dioxide in muscles
4. (D) Oxygen in muscles

8. The walls of alveoli are broken in:

1. (A) Pneumonia
2. (B) Bronchitis
3. (C) Emphysema ✓
4. (D) Asthma

9. Smoking leads to lung cancer by:

1. (A) Increasing oxygen uptake
2. (B) Promoting uncontrolled cell division ✓
3. (C) Slowing down healing
4. (D) Enlarging the trachea

10. Which chemical in cigarette smoke directly leads to addiction?

1. (A) Carbon monoxide
2. (B) Tar
3. (C) Nicotine ✓
4. (D) Formaldehyde

11. Which of these correctly orders the structures through which air passes during inhalation?

1. (A) Pharynx → trachea → larynx → bronchi
2. (B) Larynx → pharynx → bronchi → trachea
3. (C) Larynx → pharynx → trachea → bronchi
4. (D) Pharynx → larynx → trachea → bronchi ✓

12. Breathing is a:

1. (A) digestive process
2. (B) physical process ✓
3. (C) chemical process
4. (D) biochemical process

13. Cells oxidize glucose and get energy in the process of:

1. (A) ventilation
2. (B) cellular respiration ✓
3. (C) breathing
4. (D) gaseous exchange

14. Small dust particles in the nasal cavity are trapped by:

1. (A) mucus ✓
2. (B) fine hairs
3. (C) cilia of alveoli
4. (D) the epiglottis

15. The opening at the floor of the pharynx that leads into the larynx is the:

1. (A) nostril
2. (B) bronchus
3. (C) glottis ✓
4. (D) epiglottis

16. The larynx is also called the:

1. (A) voice box ✓
2. (B) windpipe
3. (C) food pipe
4. (D) air sac

17. The length of the trachea is about:

1. (A) 30 cm
2. (B) 12 cm ✓
3. (C) 25 cm
4. (D) 4 cm

18. Plate-like cartilages are present in the walls of the:

1. (A) trachea
2. (B) alveoli
3. (C) smallest bronchioles
4. (D) bronchi ✓

19. Cartilage is absent in the walls of the:

1. (A) larynx
2. (B) smallest bronchioles ✓
3. (C) trachea
4. (D) bronchi

20. The chest wall is made up of:

1. (A) the diaphragm only
2. (B) 12 pairs of ribs and intercostal muscles ✓
3. (C) 10 pairs of ribs only
4. (D) 24 pairs of ribs