On removing the thyroid from the tadpole of frog

Options

A. Metamorphosis will stop
B. It grows into a giant frog
C. It grows into a dwarf frog
D. Normal metamorphosis occurs

Answer

**Step-by-Step Solution:**

1. **Understanding Metamorphosis in Frogs**: Metamorphosis is a biological process where a tadpole (the larval stage of a frog) transforms into an adult frog. This process involves significant physical changes, including the development of lungs and the loss of gills.

2. **Role of Thyroid Gland**: The thyroid gland produces the hormone thyroxine (T4), which is crucial for regulating metabolism and facilitating metamorphosis in amphibians. Thyroxine is responsible for the apoptosis (programmed cell death) of certain structures in the tadpole, such as gills and tail.

3. **Effect of Thyroid Removal**: If the thyroid gland is removed from a tadpole, the production of thyroxine will cease. Without thyroxine, the processes that lead to metamorphosis, including the apoptosis of gills and tail, will not occur.

4. **Consequences of Thyroid Removal**: The absence of thyroxine means that the tadpole will not undergo the necessary changes to transition into an adult frog. Instead, it will remain in the larval stage, unable to develop further.

5. **Conclusion**: Therefore, the correct answer to the question is that metamorphosis will stop, and the tadpole will remain in its larval form.

**Final Answer**: On removing the thyroid from the tadpole of a frog, metamorphosis will stop.

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