Major function of contractive vacuole is

Options

A. excretion
B. circulation
C. osmoregulation
D. all the above

Answer

**Step-by-Step Solution:**

1. **Understanding Contractile Vacuoles**:
- Contractile vacuoles are specialized organelles found in certain protozoans and some multicellular organisms like hydra. They play a crucial role in maintaining cellular homeostasis.

2. **Function of Contractile Vacuoles**:
- The primary function of contractile vacuoles is to expel excess water from the cell. This is particularly important in organisms that live in freshwater environments where the concentration of solutes outside the cell is lower than inside.

3. **Excretion of Waste**:
- In addition to expelling excess water, contractile vacuoles also help in the removal of nitrogenous wastes, such as ammonia ions, which can be toxic to the cell if allowed to accumulate.

4. **Osmoregulation**:
- The process of regulating water and solute concentrations within the cell is known as osmoregulation. The contractile vacuole plays a vital role in this process by ensuring that the cell does not take in too much water.

5. **Conclusion**:
- Given the functions discussed, the major function of the contractile vacuole can be summarized as osmoregulation, which includes the expulsion of excess water and nitrogenous wastes.

6. **Final Answer**:
- Therefore, the correct answer to the question about the major function of the contractile vacuole is **osmoregulation**.

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