Which of the following does not occur in hydra ?

Options

A. Fertilization
B. segmentation
C. regeneration
D. gastrovascular cavity

Answer

To determine which of the following does not occur in Hydra, we will analyze the options provided based on the characteristics and biological processes associated with Hydra.

### Step-by-Step Solution:

1. **Understanding Hydra**:
- Hydra is a simple aquatic organism belonging to the Phylum Cnidaria. It is known for its regenerative abilities and simple body structure.

2. **Analyze the Options**:
- We need to evaluate the biological processes or structures mentioned in the options provided (not explicitly listed in the transcript).

3. **Fertilization**:
- Hydra reproduces asexually through a process called binary fission. This means that it can reproduce by splitting itself into two parts, which is a form of fertilization, albeit asexual. Therefore, fertilization does occur in Hydra.

4. **Segmentation**:
- Segmentation refers to the division of the body into repetitive segments. This feature is characteristic of more complex organisms, particularly those in the Phylum Annelida (like earthworms). Hydra does not exhibit segmentation; it has a simple body structure without metameric segments.

5. **Regeneration**:
- Hydra has a remarkable ability to regenerate lost parts. If a Hydra is cut, it can regenerate and form new individuals from the cut parts. Therefore, regeneration does occur in Hydra.

6. **Gastrovascular Cavity**:
- Hydra possesses a gastrovascular cavity, which serves both digestive and circulatory functions. This cavity allows for the digestion of food and the distribution of nutrients throughout the body. Thus, the gastrovascular cavity is present in Hydra.

7. **Conclusion**:
- After evaluating all the options, we conclude that the characteristic that does not occur in Hydra is **segmentation**.

### Final Answer:
The correct option that does not occur in Hydra is **segmentation**.

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