Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Whenever water retention is necessary, pituitary secretes ADH
Reason (R): ADH makes the cells in the wall of collecting ducts impermeable to water.
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

ADH makes the collecting duct more permeable to water so that water is reabsorbed.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
ADH (vasopressin) is released from the posterior pituitary to help the body conserve water.

Step 2: Check the Assertion
When body fluid volume falls or blood becomes concentrated, osmoreceptors act on the hypothalamus and ADH is released. So (A) is true.

Step 3: Check the Reason
ADH makes the distal tubule and collecting duct cells permeable to water, so more water is reabsorbed. It does not make them impermeable, so (R) is false.

Step 4: Conclusion
(A) is true but (R) is false.

Final Answer:
The Assertion is true but the Reason is false. \[ \boxed{\text{(C) }\text{(A) is true but (R) is false.}} \]