Respiratory pigment of molluscs is

Options

A. Haemocyanin
B. Haemoglobin
C. Erthrocruorin
D. Chlorocruorin.

Answer

### Step-by-Step Solution:

1. **Identify the Question**: The question asks about the respiratory pigment found in molluscs.

2. **Understand the Options**: The options may include various respiratory pigments such as hemoglobin, hemocyanin, and others.

3. **Research the Respiratory Pigments**:
- **Hemoglobin**: A common respiratory pigment found in many animals, including some molluscs.
- **Hemocyanin**: A copper-containing respiratory pigment that is primarily found in molluscs and some arthropods.

4. **Determine the Correct Answer**:
- In molluscs, the predominant respiratory pigment is **hemocyanin**. This pigment is copper-based and is found in all major groups of molluscs, including bivalves, gastropods, and cephalopods.
- While some gastropods may contain hemoglobin, the majority of molluscs utilize hemocyanin for oxygen transport.

5. **Conclude the Answer**: The correct answer to the question is **hemocyanin**, which is the respiratory pigment of molluscs.

### Final Answer:
The respiratory pigment of molluscs is **hemocyanin**.

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