Which of the following is characteristic of phylum Ctenophora ?

Options

A. Diploblastic with tissue grade body organization
B. Only sexual method of reproduction but organisms are hermaphrodites
C. The body bears eight external rows of ciliated comb plates and shows bioluminescence
D. All of these

Answer

To determine the characteristics of phylum Ctenophora, we can analyze the provided options step by step:

1. **Understanding the Phylum Ctenophora**:
- Ctenophores, commonly known as comb jellies, are marine invertebrates that are known for their unique features.

2. **Evaluating the First Statement**:
- The first statement claims that Ctenophores are diploblastic with tissue-grade body organization.
- **Analysis**: Ctenophores indeed have two primary germ layers: ectoderm and endoderm, which qualifies them as diploblastic. They also exhibit a tissue-grade organization, meaning their cells are organized into tissues.
- **Conclusion**: This statement is correct.

3. **Evaluating the Second Statement**:
- The second statement suggests that Ctenophores reproduce only through sexual methods.
- **Analysis**: Ctenophores are hermaphrodites, meaning they possess both male and female reproductive organs in the same individual. While they primarily reproduce sexually, they can also reproduce asexually through other means.
- **Conclusion**: This statement is misleading as it implies exclusivity to sexual reproduction. Therefore, it is not entirely correct.

4. **Evaluating the Third Statement**:
- The third statement mentions that the body of Ctenophores appears with 8 external rows of ciliated comb plates and shows bioluminescence.
- **Analysis**: This is a defining characteristic of Ctenophores. They have eight rows of cilia (comb plates) that they use for locomotion, and many species exhibit bioluminescence.
- **Conclusion**: This statement is correct.

5. **Final Evaluation**:
- Since the first and third statements are correct, but the second statement is misleading, we conclude that the characteristics of phylum Ctenophora include being diploblastic and having tissue-grade organization, as well as possessing ciliated comb plates and bioluminescence.

**Correct Answer**: The characteristics of phylum Ctenophora include being diploblastic with tissue-grade organization and having 8 external rows of ciliated comb plates that exhibit bioluminescence.

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