Which one is polymorphic coelenterate?

Options

A. Obelia
B. Hydra
C. Aurelia
D. Adamsia.

Answer

**Step-by-Step Solution:**

1. **Understanding Polymorphism**:
- Polymorphism refers to the phenomenon where an organism exists in two or more distinct morphological (structural) and functional forms. In the context of coelenterates (also known as cnidarians), this typically refers to the presence of both polyp and medusa forms.

2. **Identifying the Options**:
- The given options are: Abellia, Hydra, Aurelia, and Adamsia. We need to determine which of these exhibits polymorphism.

3. **Analyzing Each Option**:
- **Hydra**: This organism is primarily in the polyp form and does not exhibit a medusa stage. Therefore, it is considered monomorphic.
- **Adamsia**: Similar to Hydra, Adamsia also exists only in the polyp form and does not have a medusa stage, making it monomorphic as well.
- **Aurelia**: This organism is known for its medusa stage, but it does not exhibit a polyp stage in its life cycle, thus it is also considered monomorphic.
- **Abellia**: This organism shows both polyp and medusa forms. It exhibits a life cycle that includes alternation of generations, where polyps produce medusa asexually, and medusa can produce polyps sexually.

4. **Conclusion**:
- Based on the analysis, the only organism that exhibits polymorphism (the presence of both polyp and medusa forms) is **Abellia**.

**Final Answer**: Abellia is the polymorphic coelenterate.

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