A loose mantle is present over the body in

Options

A. Echinoderms
B. Mammals
C. Platyhelminthes
D. Molluscs.

Answer

To solve the question "A loose mantle is present over the body in," we will analyze each of the given options step by step.

### Step-by-Step Solution:

1. **Understanding the Question**:
- The question asks about the presence of a loose mantle over the body of certain organisms. We need to identify which of the provided options has this characteristic.

2. **Analyzing the Options**:
- **Option A: Echinoderms**:
- Echinoderms are marine animals characterized by their radial symmetry in adults and bilateral symmetry in larvae. They do not have a mantle.
- **Option B: Mammals**:
- Mammals are characterized by the presence of mammary glands and do not possess a mantle. They develop from a zygote into a fetus and do not lay eggs.
- **Option C: Platyhelminthes**:
- Platyhelminthes, or flatworms, have a dorsoventrally flattened body but lack a mantle structure.
- **Option D: Mollusks**:
- Mollusks are characterized by the presence of a mantle, which is a significant feature of this phylum. The mantle can be loose and covers the visceral mass of the mollusk.

3. **Identifying the Correct Answer**:
- After analyzing all the options, we find that only **Mollusks** have a loose mantle present over their body. Therefore, the correct answer is **Option D: Mollusks**.

### Final Answer:
The correct option is **Mollusks** (Option D).

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