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 incorrect. Let's go through each option step by step.

### Step-by-Step Solution:

1. **Option A: Tubular reabsorption takes place by passive and active transport.**
- **Analysis:** This statement is true. Tubular reabsorption occurs in the renal tubules and involves both passive and active transport mechanisms. Active transport is used for substances like sodium ions, glucose, and amino acids, while passive transport is used for water and some nitrogenous wastes.

2. **Option B: Antidiuretic hormone decreases the reabsorption of water in distal convoluted tubule and collecting duct.**
- **Analysis:** This statement is incorrect. The antidiuretic hormone (ADH), also known as vasopressin, actually increases the reabsorption of water in the distal convoluted tubule and collecting duct. It is secreted in response to dehydration and helps the body retain water.

3. **Option C: Cortical nephrons control plasma volume under normal water supply.**
- **Analysis:** This statement is true. Cortical nephrons are located in the renal cortex and are involved in regulating plasma volume under normal hydration conditions. They have shorter loops of Henle and do not extend deep into the medulla.

4. **Option D: A normal adult person secretes about 1.5 liters of urine in 24 hours.**
- **Analysis:** This statement is also true. On average, a healthy adult produces between 800 ml to 2000 ml of urine per day, and 1.5 liters is a reasonable average.

### Conclusion:
After analyzing all the options, the statement that is not correct is **Option B**: "Antidiuretic hormone decreases the reabsorption of water in distal convoluted tubule and collecting duct." This statement is false because ADH actually increases water reabsorption.

### Final Answer:
**Option B** is the statement that is not correct.

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