In which of the following haemocyanin pigment is found?

Options

A. Annelida
B. Echinodermata
C. Insecta
D. Lower invertebrates

Explanation

### Step-by-Step Solution:

1. **Understanding Hemocyanin**:
- Hemocyanin is a respiratory pigment similar to hemoglobin but contains copper instead of iron. This gives it a blue color, unlike hemoglobin, which is red.

2. **Analyzing the Options**:
- The options provided are:
- A) Annelida
- B) Echinodermata
- C) Insecta
- D) Lower Invertebrates

3. **Evaluating Each Option**:
- **A) Annelida**:
- Major representatives like earthworms have hemoglobin as their respiratory pigment, which is red. Therefore, hemocyanin is not present in this group.
- **B) Echinodermata**:
- Echinoderms are marine animals that do not possess respiratory pigments like hemocyanin. They rely on a water vascular system for gas exchange. Hence, hemocyanin is absent here.
- **C) Insecta**:
- Insects belong to the phylum Arthropoda. While some arthropods have hemocyanin, insects do not; they have a tracheal system for respiration. Thus, hemocyanin is not found in insects.
- **D) Lower Invertebrates**:
- This category includes phylum Mollusca, which contains organisms that have hemocyanin as their respiratory pigment. This is the correct option.

4. **Conclusion**:
- The correct answer is **D) Lower Invertebrates**, as hemocyanin is found in this group, particularly in mollusks.