Select the statement that is not correct.

Options

A. Tubular reabsorption takes place by passive and active transport.
B. ADH decreases the reabsorption of water in the DCT and collecting duct.
C. Cortical nephrons control plasma volume under normal water supply.
D. A normal adult person secretes about 1.5 liters of urine in 24 hours.

Answer

To solve the question, we need to analyze each statement provided and determine which one is not correct. Here’s a step-by-step breakdown of the solution:

### Step 1: Analyze the First Statement
**Statement:** Tubular reabsorption is done by both passive and active transport.

**Analysis:** This statement is correct. Tubular reabsorption in the nephron involves both passive transport (e.g., diffusion of water and some solutes) and active transport (e.g., reabsorption of sodium ions, glucose, and amino acids).

### Step 2: Analyze the Second Statement
**Statement:** ADH reduces reabsorption in DCT and collecting duct.

**Analysis:** This statement is incorrect. Antidiuretic Hormone (ADH), also known as vasopressin, actually stimulates the reabsorption of water in the distal convoluted tubule (DCT) and collecting duct. Therefore, this statement is not correct.

### Step 3: Analyze the Third Statement
**Statement:** Cortical nephrons, under normal water supply, control plasma volume.

**Analysis:** This statement is correct. Cortical nephrons are located in the outer part of the kidney and play a significant role in regulating plasma volume and filtering blood.

### Step 4: Analyze the Fourth Statement
**Statement:** A normal adult produces 1.5 liters of urine in 24 hours.

**Analysis:** This statement is also correct. A normal adult typically produces about 1 to 1.5 liters of urine daily.

### Conclusion
After analyzing all the statements, we find that the second statement regarding ADH is the only incorrect one.

### Final Answer
The statement that is not correct is: **"ADH reduces reabsorption in DCT and collecting duct."**

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