Question

The secondary function of lungs to carry out excretion is ____ .

• A. Removal of CO₂ and Water
• B. Elimination of Sebum
• C. Urea formation
• D. Excretion of excess salts

Answer 1

The Correct Option is A

To solve this question, we need to identify the secondary excretory function performed by the lungs.

1. Understanding Lung Functions:
The primary function of the lungs is respiration, which involves gas exchange—taking in oxygen (O₂) and expelling carbon dioxide (CO₂).

2. Secondary Excretory Function:
Apart from their primary respiratory function, lungs also play an excretory role by eliminating gaseous metabolic waste products, specifically carbon dioxide (CO₂) and water vapor (H₂O).

3. Evaluating Given Options:
 

• (1) Removal of CO₂ and Water – Correct, lungs excrete carbon dioxide and water vapor.
• (2) Elimination of Sebum – Incorrect, sebum is secreted by sebaceous glands in the skin.
• (3) Urea formation – Incorrect, urea is formed in the liver, not lungs.
• (4) Excretion of excess salts – Incorrect, excess salts are primarily removed by kidneys and sweat glands.

Final Answer:
The correct answer is (A) Removal of CO₂ and Water.