Which statement is true for Paramecium ?

Options

A. 2 contractile vacuoles work alternately
B. Anterior contractile vacuole work more frequently
C. Posterior contractile vacuole work more frequently
D. None of the above.

Answer

To determine which statement is true for Paramecium regarding its contractile vacuoles, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Paramecium**:
Paramecium is a unicellular eukaryote that has a complex structure, including two contractile vacuoles.

2. **Identify the Function of Contractile Vacuoles**:
The primary function of contractile vacuoles in Paramecium is to help remove excess water and waste from the cell. This is crucial for maintaining osmotic balance.

3. **Locate the Position of Contractile Vacuoles**:
In Paramecium, there are two contractile vacuoles located between the endoplasm and ectoplasm. They are positioned at fixed locations within the cell.

4. **Examine the Activity of the Contractile Vacuoles**:
The contraction of the contractile vacuoles occurs irregularly. However, there is a distinction between the anterior and posterior contractile vacuoles regarding their frequency of contraction.

5. **Compare Anterior and Posterior Contractile Vacuoles**:
The anterior contractile vacuole is located at the front of the cell, while the posterior contractile vacuole is located near the cytopharynx at the back. It has been observed that the posterior contractile vacuole works more frequently than the anterior one.

6. **Select the Correct Statement**:
Based on the information gathered, the true statement regarding Paramecium is that the posterior contractile vacuole works more frequently than the anterior one.

### Conclusion:
The correct answer to the question is that the posterior contractile vacuole works more frequently.

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