Body of molluscs is

Options

A. Unsegmented
B. Covered by a calcareous shell
C. Divided into distinct head muscular foot and visceral hump
D. All of these

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Body Structure of Molluscs**:
- Molluscs are a diverse group of invertebrates classified under the phylum Mollusca. They are characterized by their unique body structure.

2. **Unsegmented Body**:
- The body of molluscs is unsegmented. This means that unlike annelids (segmented worms) or arthropods (which have distinct segments), the body of a mollusc does not exhibit segmentation. For example, in snails, the body is not divided into segments.

3. **Presence of a Calcareous Shell**:
- Many molluscs, such as snails, have a calcareous shell that covers their body. This shell is made of calcium carbonate and serves as a protective barrier against predators and environmental hazards. The shell allows the mollusc to retract into it for safety.

4. **Distinct Body Regions**:
- The body of molluscs is divided into three main parts:
- **Head**: Contains sensory organs and the mouth.
- **Muscular Foot**: A muscular structure used for locomotion and attachment.
- **Visceral Hump**: Contains the internal organs and is often covered by the shell.

5. **Conclusion**:
- All the statements regarding the body of molluscs are correct. The body is unsegmented, covered by a calcareous shell, and divided into distinct regions (head, muscular foot, and visceral hump).

### Final Answer:
The body of molluscs is unsegmented, covered by a calcareous shell, and divided into distinct head, muscular foot, and visceral hump. Therefore, all of these statements are correct.

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