' Contractile vacuole ' play important role in excretion in

Options

A. Amoeba
B. Paramecium
C. Hydra
D. both (A)&(B)

Answer

**Step-by-Step Solution:**

1. **Understanding Contractile Vacuole**:
- The contractile vacuole is a specialized organelle found in certain unicellular organisms. Its primary function is to regulate water balance and remove excess water from the cell, which is crucial for maintaining homeostasis.

2. **Identifying Organisms with Contractile Vacuoles**:
- We need to determine which of the given options possess contractile vacuoles and utilize them for excretion.

3. **Analyzing the Options**:
- **Option A: Amoeba**:
- Amoeba is a unicellular organism that utilizes contractile vacuoles to expel excess water and waste products. Therefore, this option is correct.

- **Option B: Paramecium**:
- Paramecium is another unicellular organism that also possesses contractile vacuoles. These vacuoles help in the excretion of waste and regulation of water. Thus, this option is also correct.

- **Option C: Hydra**:
- Hydra is a multicellular organism and does not rely on contractile vacuoles for excretion. Instead, it uses specialized excretory organs and structures. Therefore, this option is incorrect.

- **Option D: A and B**:
- This option combines both Amoeba and Paramecium, both of which utilize contractile vacuoles for excretion. Hence, this option is correct.

4. **Conclusion**:
- The correct answer is **Option D**: A and B, as both Amoeba and Paramecium utilize contractile vacuoles for excretion.