In molluscs, head and foot regions have come together in

Options

A. Scaphopodas
B. Pelecypods
C. Siphonopods
D. Both A and B

Answer

To solve the question "In molluscs, head and foot regions have come together in," we need to analyze the different classes of mollusks and determine which one has the head and foot regions merged. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which class of molluscs has the head and foot regions combined.

2. **Identify the Classes of Molluscs**: The main classes of molluscs include:
- Scaphopoda (tusk shells)
- Bivalvia (clams, oysters)
- Cephalopoda (squids, octopuses)

3. **Analyze Scaphopoda**:
- In Scaphopoda, the body is elongated and tubular, and the head and foot are not merged.
- Example: Dentallium is a scaphopod and demonstrates this structure.

4. **Analyze Bivalvia**:
- Bivalves have two shells and a distinct head and foot. The head and foot are not merged in this class.
- Example: Pearl oyster is a bivalve and shows that the head and foot are separate.

5. **Analyze Cephalopoda**:
- In Cephalopoda, the name itself indicates a combination of head (cephalo) and foot (poda).
- The head and foot are merged to form a complex body structure, which includes tentacles and eyes.
- Example: Octopus is a cephalopod where the head and foot are indistinguishable.

6. **Conclusion**: Based on the analysis, the class in which the head and foot regions have come together is **Cephalopoda**.

7. **Final Answer**: The correct option is **Option 3: Cephalopoda**.