Melatonin is secreted by

Options

A. pinearl body
B. skin
C. Pituitary gland
D. thyroid.

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks where melatonin is secreted from.

2. **Review the Options**: The options provided are:
- Pineal body
- Skin
- Pituitary gland
- Thyroid

3. **Understand the Function of Melatonin**: Melatonin is a hormone that plays a role in regulating sleep-wake cycles and is also involved in skin pigmentation and reproductive functions.

4. **Locate the Source of Melatonin**: The pineal body, also known as the pineal gland, is a small gland located in the brain.

5. **Confirm the Function of the Pineal Body**: The pineal body is known to secrete melatonin, which is crucial for regulating circadian rhythms and other biological functions.

6. **Eliminate Incorrect Options**:
- Skin does not secrete melatonin.
- The pituitary gland is involved in hormone regulation but does not secrete melatonin.
- The thyroid gland is responsible for metabolism regulation and does not produce melatonin.

7. **Conclude the Answer**: Based on the information, the correct answer is that melatonin is secreted by the pineal body.

**Final Answer**: Melatonin is secreted by the pineal body.

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