Which endocrine gland is essential for metamorphosis of tadpole ?

Options

A. Adrenals
B. Thyroid gland
C. Thymus
D. Pituitary gland

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which endocrine gland is essential for the metamorphosis of tadpoles. Metamorphosis is the process by which a tadpole transforms into a frog.

2. **Identifying the Options**: The options provided are:
- Adrenal gland
- Thyroid gland
- Thymus gland
- Pituitary gland

3. **Evaluating Each Option**:
- **Adrenal Gland**: This gland has two parts (adrenal cortex and adrenal medulla) and produces hormones like adrenaline. It is not involved in the metamorphosis of tadpoles.
- **Thyroid Gland**: This gland produces thyroxine, a hormone crucial for the metamorphosis process in amphibians. It stimulates the transformation of the tadpole into a frog.
- **Thymus Gland**: This gland produces thymosine, which is important for T-cell development in the immune system, but not for metamorphosis.
- **Pituitary Gland**: Known as the master gland, it secretes various hormones but is not directly responsible for the metamorphosis of tadpoles.

4. **Conclusion**: The correct answer is the **Thyroid Gland**, as it secretes thyroxine, which is essential for the metamorphosis of tadpoles into frogs.

**Final Answer**: The endocrine gland essential for the metamorphosis of tadpoles is the **Thyroid Gland**.

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