Contractile vacuoles in Paramecium are

Options

A. 2 in number
B. 6 in number
C. 6 to 10 in number
D. 1 in number

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the number of contractile vacuoles present in Paramecium.

2. **Identifying the Organism**: Paramecium is a unicellular organism that lives in freshwater environments. It is a ciliate, meaning it has hair-like structures called cilia that help it move.

3. **Function of Contractile Vacuoles**: Contractile vacuoles are specialized structures in Paramecium that help regulate water content within the cell. They are crucial for osmoregulation, which is the process of maintaining the balance of water and solutes in the organism.

4. **Water Movement in Freshwater**: In freshwater, the concentration of solutes outside the Paramecium is lower than inside the cell. This difference in concentration causes water to flow into the Paramecium, which could lead to the cell bursting (lysis) if not regulated.

5. **Number of Contractile Vacuoles**: Paramecium has two contractile vacuoles—one located at the anterior (front) and the other at the posterior (back) end of the cell.

6. **Process of Osmoregulation**: The contractile vacuoles absorb excess water that enters the cell. They expand to accommodate the water and then contract to expel the water out of the cell, thus preventing lysis.

7. **Conclusion**: Therefore, the correct answer to the question is that Paramecium has **2 contractile vacuoles**.

### Final Answer:
Contractile vacuoles in Paramecium are **2 in number**.

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