Which of the following normone helps in facultative water reabsorption by nephrons :-

Options

A. MSH
B. FSH
C. ADH
D. ACTH

Answer

To solve the question regarding which hormone helps in facultative water reabsorption by nephrons, we can follow these steps:

### Step 1: Understand the question
The question asks which hormone is responsible for facultative water reabsorption in the nephrons, which are the functional units of the kidney.

### Step 2: Identify the hormones listed
The options given are:
1. MSH (Melanocyte Stimulating Hormone)
2. FSH (Follicle Stimulating Hormone)
3. ADH (Antidiuretic Hormone)
4. ECTH (Adrenocorticotropic Hormone)

### Step 3: Analyze each hormone
- **MSH (Melanocyte Stimulating Hormone)**: This hormone primarily regulates skin pigmentation and does not play a role in water reabsorption.

- **FSH (Follicle Stimulating Hormone)**: This hormone is involved in the reproductive processes, particularly in the development of gametes, and does not influence water reabsorption in the kidneys.

- **ADH (Antidiuretic Hormone)**: Also known as vasopressin, this hormone is crucial for water reabsorption in the kidneys. It acts on the nephrons to promote the reabsorption of water back into the bloodstream, thus reducing urine output and conserving water in the body.

- **ECTH (Adrenocorticotropic Hormone)**: This hormone stimulates the adrenal glands to produce cortisol and other hormones but does not directly affect water reabsorption in the nephrons.

### Step 4: Identify the correct answer
Based on the analysis, the hormone that helps in facultative water reabsorption by nephrons is **ADH (Antidiuretic Hormone)**.

### Final Answer
The correct option is **ADH (Antidiuretic Hormone)**.

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