In which phylum blood pigment is haemo-
cyanin ?

Options

A. echinodermata
B. molluscs
C. platyhelminthes
D. aschelminthes

Answer

To determine in which phylum the blood pigment hemocyanin is found, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Hemocyanin**:
- Hemocyanin is a type of respiratory pigment that is used by some animals to transport oxygen. It is different from hemoglobin, which is found in vertebrates.

2. **Identifying the Elements in Hemocyanin**:
- Hemocyanin contains copper ions, which give it a blue color when oxygenated. This is a key characteristic that differentiates it from other respiratory pigments.

3. **Reviewing the Options**:
- The options given are:
1. Agynecomastia
2. Mollusca
3. Platyhelminthes
4. SK Helminthes

4. **Analyzing Each Phylum**:
- **Agynecomastia**: This is not a recognized phylum in biological classification.
- **Mollusca**: This phylum includes animals like octopuses and squids, which are known to use hemocyanin as their oxygen-carrying pigment.
- **Platyhelminthes**: This phylum includes flatworms, which do not have hemocyanin; they typically lack a circulatory system.
- **SK Helminthes**: This is likely a misrepresentation or abbreviation of a helminth group (like nematodes or flatworms), which also do not utilize hemocyanin.

5. **Conclusion**:
- Based on the analysis, hemocyanin is primarily found in the phylum **Mollusca** and also in some members of the phylum **Arthropoda**. However, since the question specifically asks for one phylum, the correct answer is **Mollusca**.

### Final Answer:
- The blood pigment hemocyanin is found in the phylum **Mollusca**.