Assertion: In Pleurobrachia, eight comb like ciliary plates called comb plates are present on the body that help in locomotion.
Reason: Pleurobrachia reproduces sexually and its life cycle includes cydippid larva.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the assertion and reason question regarding Pleurobrachia, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states: "In Pleurobrachia, eight comb-like ciliary plates called comb plates are present on the body that help in locomotion."

- **Explanation**: Pleurobrachia is a genus of ctenophores, which are marine organisms known for their unique locomotion mechanism. The eight comb plates (or ciliary plates) are indeed characteristic features of ctenophores. These plates are lined with cilia that beat in a coordinated manner, allowing the organism to swim through the water.

**Conclusion**: The assertion is true.

### Step 2: Analyze the Reason
The reason states: "Pleurobrachia reproduces sexually and its life cycle includes cydippid larva."

- **Explanation**: Pleurobrachia does reproduce sexually, and it is known to have a life cycle that includes a cydippid larva stage. Cydippid larvae are the free-swimming larval stage of ctenophores, which develop from fertilized eggs. This aligns with the known reproductive strategy of ctenophores, which typically involves external fertilization.

**Conclusion**: The reason is also true.

### Step 3: Determine the Relationship Between Assertion and Reason
Now we need to determine if the reason correctly explains the assertion.

- The assertion talks about the presence of comb plates for locomotion, while the reason discusses reproduction and larval stages. Although both statements are true, the reason does not provide a direct explanation for the assertion regarding locomotion.

**Final Conclusion**: Both the assertion and reason are true, but the reason does not correctly explain the assertion. Therefore, the correct answer is that both statements are true, but the reason is not the correct explanation of the assertion.

### Final Answer
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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