Tentacles of Obelia are

Options

A. Hollow
B. Solid
C. Internally chambered
D. Spiny and hollow.

Answer

**Step-by-Step Solution:**

1. **Understanding Obelia**: Begin by recognizing that Obelia is a colonial organism, which means it consists of a group of genetically identical individuals (polyps) that live together.

2. **Life Forms of Obelia**: Obelia has two distinct life forms: the polyp and the medusa. The polyp is the stage that bears the tentacles.

3. **Tentacle Characteristics**: The tentacles of Obelia typically range from 20 to 30 in number. This is an important characteristic to note.

4. **Structure of Tentacles**: When examining the structure of the tentacles, it is essential to understand that they are solid in nature. This means that if you were to cut through a tentacle, you would find that it does not have a hollow center.

5. **Internal Composition**: Inside the solid tentacle, endodermal cells are present. This indicates that the tentacle is not only solid but also has a specific cellular structure that contributes to its function.

6. **Conclusion**: Based on the characteristics and structure of the tentacles, the correct answer to the question "Tentacles of Obelia are" is that they are solid.

**Final Answer**: The tentacles of Obelia are solid.

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