What is not similar in coelenterata and ctenophora?

Options

A. Body wall
B. Digestion
C. Symmetry
D. Metagenesis

Answer

To answer the question "What is not similar in Coelenterata and Ctenophora?", we will analyze each option provided and identify the differences between these two groups of organisms.

### Step-by-Step Solution:

1. **Understanding Coelenterata and Ctenophora**:
- Coelenterata, also known as Cnidaria, includes organisms like jellyfish, corals, and sea anemones.
- Ctenophora, commonly known as comb jellies, are another group of aquatic animals.

2. **Analyzing the Options**:
- **Option 1: Body Wall**:
- Both Coelenterata and Ctenophora have a diploblastic body structure, meaning they are composed of two germ layers: ectoderm and endoderm. Therefore, this option is similar in both groups.

- **Option 2: Digestion**:
- Coelenterata exhibit both extracellular and intracellular digestion. In contrast, Ctenophora primarily have extracellular digestion. This indicates a difference in their digestive processes.

- **Option 3: Symmetry**:
- Both Coelenterata and Ctenophora exhibit radial symmetry, meaning they are symmetrical around a central axis. Thus, this option is also similar in both groups.

- **Option 4: Metagenesis**:
- Metagenesis refers to the alternation of generations, specifically between sexual and asexual reproduction. Coelenterata often exhibit metagenesis, while Ctenophora do not have this reproductive strategy. Therefore, this is a significant difference.

3. **Conclusion**:
- The aspect that is not similar between Coelenterata and Ctenophora is **metagenesis**. Coelenterata can undergo metagenesis, while Ctenophora do not.

### Final Answer:
The characteristic that is not similar in Coelenterata and Ctenophora is **metagenesis**.