Which of the following element should be available in water for metamorphosis of tadpoles ?

Question

Accepted Answer

The correct answer to the question is Option 3: Iodine. Here is a detailed explanation supporting this choice:

1. **Explanation for Option 3 (Iodine):**
   Iodine is an essential element required for the synthesis of thyroid hormones, which play a crucial role in the process of metamorphosis in amphibians, including tadpoles. These hormones regulate the transformation of tadpoles into adult frogs by controlling the development of various organs and systems. Without adequate iodine, the production of thyroid hormones is impaired, leading to disrupted or incomplete metamorphosis. Therefore, the presence of iodine in water is vital for the successful metamorphosis of tadpoles.

2. **Explanation for why other options are incorrect:**

- **Option 1 (Sulphur):**
     Sulphur is not directly involved in the metamorphosis of tadpoles. While it is a component of some amino acids and proteins, it does not play a specific role in the hormonal regulation required for metamorphosis. Therefore, its presence in water is not critical for this process.

- **Option 2 (Chlorine):**
     Chlorine is commonly used to disinfect water and is not a biological requirement for metamorphosis. It does not contribute to the hormonal changes necessary for the transformation of tadpoles into frogs. In fact, excessive chlorine can be harmful to aquatic life.

- **Option 4 (Carbon):**
     Carbon is a fundamental element in all living organisms, forming the backbone of organic molecules. However, it does not have a specific role in the metamorphosis of tadpoles. The process of metamorphosis is hormonally driven, and carbon does not influence the production or function of these hormones.

In conclusion, iodine is the correct and essential element required in water for the metamorphosis of tadpoles, as it is crucial for the synthesis of thyroid hormones that drive this developmental process.