Question

Which of the following statements are true about respiration?

(i) During inhalation, ribs move inward, and the diaphragm moves up.

(ii) The gaseous exchange takes place in the alveoli.

(iii) Hemoglobin has a greater affinity for carbon dioxide than oxygen.

(iv) Alveoli increase surface area for the exchange of gases.

• A. (i) only
• B. (iii) only
• C. (ii) and (iv)

Answer 1

The correct option is C

(ii) and (iv)

The correct option is (C) (ii) and (iv).

The explanation of the correct options:

1. The exchange of gases happens in the millions of alveoli in the lungs and the capillaries.
2. The oxygen inhaled moves from the alveoli to the blood in the capillaries.
3. The carbon dioxide from the blood moves in the capillaries to the air in the alveoli.
4. Alveoli are the tiny,balloon-like air sacs that increases the surface area for the exchange of gases.

The explanation of the incorrect options :

Option A:

1. During inhalation, the ribs move outward and upward.
2. When we inhale, the contraction of the diaphragm occurs, moves downward, and increases the space in the chest cavity, and the lungs expand.

Option B:

1. Hemoglobin has a higher affinity for smaller molecules.
2. Hemoglobin has less affinity for CO₂ than oxygen because carbon dioxide is a larger molecule than oxygen.

Final Answer: The true statements about respiration are that the gaseous exchange takes place in the alveoli and the alveoli increase surface area for the exchange of gases.