Which of the following sets consist of pseudocoelomate organisms ?

Options

A. Ascaris , Ancylostoma
B. Fasciola, Earthworm
C. Roundworm , Taperworm
D. Taenia , Fasciola

Answer

To determine which set consists of pseudocoelomate organisms, we need to understand the classification of organisms based on the presence or absence of a coelom.

### Step-by-Step Solution:

1. **Understanding Coelom Types**:
- **Acoelomates**: Organisms that do not have a coelom (body cavity). Examples include flatworms (Phylum Platyhelminthes).
- **Eucoelomates**: Organisms that have a true coelom, which is a body cavity lined by mesoderm. Examples include annelids (Earthworms).
- **Pseudocoelomates**: Organisms that have a pseudocoelom, which is a fluid-filled cavity between the endoderm and mesoderm but is not lined by mesoderm. Examples include roundworms (Phylum Nematoda).

2. **Analyzing the Options**:
- **Option A: Ascaris and Cyclostoma**:
- Ascaris (a roundworm) is a pseudocoelomate.
- Cyclostoma (jawless fish) is not a pseudocoelomate; it is a eucoelomate.
- **Option B: Fasciola and Earthworm**:
- Fasciola (a liver fluke) is an acoelomate.
- Earthworm is a eucoelomate.
- **Option C: Roundworm and Tapeworm**:
- Roundworm (Ascaris) is a pseudocoelomate.
- Tapeworm (Taenia) is an acoelomate.
- **Option D: Taenia and Fasciola**:
- Both Taenia and Fasciola are acoelomates.

3. **Identifying the Correct Set**:
- From the analysis, the only organism that is a pseudocoelomate is Ascaris.
- The other organisms in the options either belong to acoelomates or eucoelomates.

4. **Conclusion**:
- The correct answer is **Option A: Ascaris and Cyclostoma**. However, since Cyclostoma is not a pseudocoelomate, the better option would be to consider only Ascaris as a pseudocoelomate.

### Final Answer:
- The set that consists of pseudocoelomate organisms is **Option A: Ascaris** (though Cyclostoma is not pseudocoelomate).