Secretion of shell in molluscs take place by :-

Options

A. Foot
B. Ink gland
C. Radula
D. Mantle

Answer

To determine which structure is responsible for the secretion of the shell in molluscs, we can analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Options**:
- We have four options to consider:
1. Foot
2. Ink gland
3. Radula
4. Mantle

2. **Evaluating Option 1: Foot**:
- The foot in molluscs is primarily a muscular structure used for locomotion and anchorage. It does not play a role in shell secretion.
- **Conclusion**: This option is incorrect.

3. **Evaluating Option 2: Ink Gland**:
- The ink gland is used by some molluscs to produce ink for defense. It does not contribute to the formation of the shell.
- **Conclusion**: This option is incorrect.

4. **Evaluating Option 3: Radula**:
- The radula is a specialized feeding organ in molluscs, which is used to scrape food. It is not involved in shell secretion.
- **Conclusion**: This option is incorrect.

5. **Evaluating Option 4: Mantle**:
- The mantle is a significant part of the mollusc anatomy that secretes the shell. It is a layer of tissue that covers the internal organs and is responsible for the formation and secretion of the shell.
- **Conclusion**: This option is correct.

### Final Answer:
The secretion of the shell in molluscs takes place by the **mantle**.

---