A hormone responsible for normal sleep wake cycle is

Options

A. epinephrine.
B. gastrin.
C. melatonin.
D. insulin.

Answer

To solve the question regarding the hormone responsible for the normal sleep-wake cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Question**: The question asks for a hormone that regulates the normal sleep-wake cycle.

2. **Review the Options**: The options provided are:
- A) Apinephrine
- B) Gastrin
- C) Melatonin
- D) Insulin

3. **Analyze Each Option**:
- **A) Apinephrine**: This hormone, also known as adrenaline, is secreted by the adrenal glands during stress or emergencies. It is not related to the sleep-wake cycle.
- **B) Gastrin**: This hormone is secreted in the stomach and is involved in the regulation of gastric acid secretion and motility. It does not play a role in the sleep-wake cycle.
- **C) Melatonin**: This hormone is secreted by the pineal gland and is known to regulate the sleep-wake cycle and circadian rhythms. It is directly involved in promoting sleep.
- **D) Insulin**: This hormone is produced by the pancreas and regulates blood sugar levels. It is not associated with the sleep-wake cycle.

4. **Determine the Correct Answer**: Based on the analysis, the hormone responsible for the normal sleep-wake cycle is **Melatonin**.

5. **Final Answer**: The correct answer is **C) Melatonin**.