What will happen if thyroid is removed from a tadpole ?

Options

A. The adpole will grow into dwar frog
B. The larva will produce giant frog
C. It will continue indefintiely in larval stage
D. The larva will die

Answer

### Step-by-Step Solution:

1. **Understanding Metamorphosis**:
- Metamorphosis is the process of transformation that an animal undergoes during its life cycle. In frogs, it begins with the hatching of eggs into tadpoles, which then undergoes several developmental stages to become adult frogs.

2. **Role of Thyroid Gland**:
- The thyroid gland produces the hormone thyroxin (T4), which is crucial for the metamorphosis of tadpoles into adult frogs. This hormone initiates the apoptosis (programmed cell death) of specific cells, such as those in the gills and tail, allowing the tadpole to transform into a frog.

3. **Effects of Thyroid Removal**:
- If the thyroid gland is removed from a tadpole, it will not produce thyroxin. Without this hormone, the metamorphosis process will be halted.

4. **Consequences of Halted Metamorphosis**:
- Since the metamorphosis is interrupted, the tadpole will remain in its larval stage indefinitely. It will not develop into an adult frog, as the necessary hormonal changes that facilitate this transformation will not occur.

5. **Evaluating the Options**:
- Option 1: "Tadpole will grow into a dwarf frog" - Incorrect, as it will not develop into any frog.
- Option 2: "Larva will produce a giant frog" - Incorrect, as it will not develop into any frog.
- Option 3: "It will continue indefinitely in the larval stage" - Correct, as the tadpole will remain a tadpole.
- Option 4: "The larva will die" - Incorrect, as the tadpole will not die but will remain in the larval stage.

6. **Conclusion**:
- The correct answer is that the tadpole will continue indefinitely in the larval stage if the thyroid is removed.