Assertion (A): Organisms belonging to cnidaria do not possess coelom.
Reason (R): Cnidarians are diploblastic animals.

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

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that organisms belonging to the phylum Cnidaria do not possess a coelom. A coelom is a fluid-filled body cavity that is completely lined by mesoderm.

2. **Analyzing Cnidarians**: Cnidarians, which include jellyfish, corals, and sea anemones, are indeed known to lack a true coelom. Instead, they have a simple body structure consisting of two layers of cells: the outer ectoderm and the inner endoderm, with a gelatinous substance called mesoglea in between.

3. **Understanding the Reason**: The reason provided states that Cnidarians are diploblastic animals. Diploblastic organisms have two germ layers (ectoderm and endoderm) and do not develop a mesoderm layer, which is essential for the formation of a coelom.

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