Assertion (A): Coelenterates may form corals.
Reason (R): Coelenterates possess hard calcareous exoskeleton.

Options

A. Both A and R are true and R is the correct explanation for A.
B. Both A and R are true but R is not the correct explanation for A.
C. A is true and R is false.
D. A is false and R is true.

Explanation

To analyze the assertion and reason provided in the question, we will break down the statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Coelenterates may form corals."
- Coelenterates, which include organisms like corals, jellyfish, and sea anemones, are indeed capable of forming coral structures. This is true because corals are a type of coelenterate (specifically, they belong to the class Anthozoa).

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