Respiratory pigment of molluscs is

Options

A. haemocyanin
B. haemoglobin
C. erythrocruorin
D. none of these

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks for the respiratory pigment found in molluscs. Respiratory pigments are molecules that facilitate the transport of oxygen in the blood of various organisms.

2. **Identifying the Options:** The options provided are:
- Haemocyanin
- Haemoglobin
- Erythrocryonin
- None of these

3. **Defining Respiratory Pigments:** Respiratory pigments are crucial for gas exchange, which involves the intake of oxygen and the release of carbon dioxide. Different organisms have different respiratory pigments.

4. **Analyzing Molluscs:** Molluscs are a diverse group of invertebrates that include snails, clams, and octopuses. It is important to identify the specific respiratory pigment they use.

5. **Identifying the Correct Pigment:**
- Haemoglobin is a common respiratory pigment found in many animals, including vertebrates, but it is not the primary pigment in molluscs.
- Erythrocryonin is not widely recognized as a respiratory pigment in molluscs.
- Haemocyanin is known to be the respiratory pigment in many molluscs and some arthropods, such as crustaceans.

6. **Understanding Haemocyanin:**
- Haemocyanin contains copper ions, which bind to oxygen.
- It gives the blood a blue color due to the presence of these copper ions.

7. **Conclusion:** The correct answer to the question is **haemocyanin**, as it is the primary respiratory pigment found in molluscs.

**Final Answer:** The respiratory pigment of molluscs is **haemocyanin**.

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