Nervous system of ctenophores is similar to

Options

A. cnidaria
B. platyhelminthes
C. parazoa
D. sponges

Answer

To answer the question about the similarity of the nervous system of ctenophores, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ctenophores**: Ctenophores, also known as comb jellies, belong to a phylum characterized by a simple and primitive nervous system. They do not possess a centralized brain or a complex nervous system.

2. **Nervous System Structure**: The nervous system in ctenophores is organized as a nerve net. This means that instead of having a centralized structure, the nerves are arranged in a mesh-like network, allowing for basic coordination of movements.

3. **Comparison with Other Phyla**: To find a similar nervous system, we need to look at other phyla. The phylum that shares a similar nerve net structure is the phylum **Cnidaria**. Like ctenophores, cnidarians (which include jellyfish, corals, and sea anemones) also exhibit a nerve net.

4. **Elimination of Other Options**:
- **Platyhelminthes** (flatworms) have a more advanced nervous system with a centralized structure, so they do not match.
- **Porifera** (sponges) lack a nervous system entirely, so they are also not similar.
- Therefore, the only phylum that exhibits a similar nerve net organization is **Cnidaria**.

5. **Conclusion**: The nervous system of ctenophores is similar to that of the phylum **Cnidaria**.

### Final Answer:
The nervous system of ctenophores is similar to that of the phylum **Cnidaria**.