The metagenesis is seen in -

Options

A. Hydra
B. Adamsia (sea anemone)
C. Aurelia
D. Obelia

Answer

To answer the question about where metagenesis is seen, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Metagenesis**:
- Metagenesis is a biological process that involves alternating generations, typically seen in certain organisms where both asexual and sexual reproduction occur. This is common in some algae and primitive plants.

2. **Analyzing the Options**:
- **Hydra**: This is a freshwater organism that reproduces asexually through budding and can also reproduce sexually. However, it does not exhibit metagenesis.
- **Adamphia**: This appears to be a typo or a less commonly known organism. It is not widely recognized in the context of metagenesis.
- **Aurelia**: This is a genus of jellyfish that undergoes a life cycle involving both polyp and medusa forms, but it does not strictly follow the metagenesis process.
- **Obelia**: This is a colonial organism that exhibits metagenesis. It has both a polyp stage (asexual reproduction) and a medusa stage (sexual reproduction), fitting the definition of metagenesis.

3. **Conclusion**:
- Based on the definitions and characteristics of the organisms listed, the correct answer is **Obelia**, as it is the only option that clearly demonstrates the process of metagenesis.

### Final Answer:
The metagenesis is seen in **Obelia**.