Melatonin is a hormone secreted by -

Options

A. Pineal
B. Pituitary
C. Thymus
D. Adrenal cortex

Answer

**Step-by-Step Solution:**

1. **Identify the Hormone in Question**: The question asks about the hormone "melatonin."

2. **Locate the Source of Melatonin**: Melatonin is secreted by the pineal gland, which is located in the brain.

3. **Understand the Nature of Melatonin**: Melatonin is derived from the amino acid tryptophan, making it a tryptophan amino acid derivative hormone.

4. **Recognize the Function of Melatonin**: The primary function of melatonin is to regulate the daily wake cycle and circadian rhythms in the body.

5. **Evaluate the Options**: The options provided in the question likely include various glands. The correct answer is the pineal gland, as it is the only gland that secretes melatonin.

6. **Conclude the Answer**: Therefore, melatonin is secreted by the pineal gland.

**Final Answer**: Melatonin is a hormone secreted by the pineal gland.

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