Excretion in Hydra occurs through

Options

A. Flame cells
B. Nephridia
C. Cnidoblasts
D. General body surface

Answer

**Step-by-Step Solution:**

1. **Understanding Hydra**: Hydra is a simple aquatic organism that belongs to the phylum Cnidaria and class Hydrozoa. It has a cylindrical shape and is sessile, meaning it is attached to a substrate.

2. **Excretory Structures in Organisms**: Different organisms have specialized structures for excretion. For example:
- **Flame Cells**: These are specialized excretory organs found in organisms of the phylum Platyhelminthes (flatworms).
- **Nephridia**: These are excretory structures found in organisms of the phylum Annelida (segmented worms).
- **Nidoblasts**: These are specialized cells in Cnidarians, but they are not involved in excretion; rather, they are used for capturing prey and defense.

3. **Excretion in Hydra**: Hydra does not possess specialized excretory organs like flame cells or nephridia. Instead, it excretes waste products through its general body surface by the process of diffusion. This means that waste materials move from an area of higher concentration inside the body to an area of lower concentration outside.

4. **Conclusion**: Based on the above analysis, the correct answer to the question "Excretion in Hydra occurs through" is the general body surface.

**Final Answer**: Excretion in Hydra occurs through the general body surface.

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