Limax and Helix respire with the help of

Options

A. Ctenidia
B. General body surface
C. Pulmonary sac
D. Buccal cavity.

Answer

### Step-by-Step Solution:

1. **Identify the Organisms**: The question asks about Limax and Helix, which are both types of land molluscs. Limax is a land slug, while Helix refers to a genus of land snails.

2. **Classify the Organisms**: Both Limax and Helix belong to the class Gastropoda, which includes all land molluscs.

3. **Understand the Respiration Mechanism**: The question is focused on how these organisms respire. In terrestrial molluscs, respiration occurs through specialized structures.

4. **Identify the Correct Respiratory Structure**: Among the options provided (tineidia, general body surface, pulmonary sac, buccal cavity), the pulmonary sac is the correct answer.

5. **Explain the Function of the Pulmonary Sac**: The pulmonary sac is a hollow organ that functions similarly to lungs in terrestrial molluscs. It has a contractile exterior opening that allows for gas exchange.

6. **Eliminate Incorrect Options**:
- **Tineidia**: These are respiratory organs found in some aquatic molluscs, not in Limax and Helix.
- **General Body Surface**: While some organisms can respire through their body surface, Limax and Helix specifically use the pulmonary sac.
- **Buccal Cavity**: This is involved in feeding and not respiration.

7. **Final Answer**: Therefore, Limax and Helix respire with the help of the **pulmonary sac**.