First time excretory organs were developed in-

Options

A. protozoa
B. flatworms
C. Annelids
D. insects

Answer

To answer the question about when excretory organs first developed, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Excretion in Protozoa**:
- Protozoa are unicellular organisms that do not have specialized excretory organs. They rely on diffusion to remove waste materials from their bodies.
- **Conclusion**: Protozoa do not have developed excretory organs.

2. **Examining Flatworms**:
- Flatworms, which are more complex than protozoa, possess specialized excretory cells known as flame cells. These cells are responsible for the excretion of waste materials.
- **Conclusion**: Flatworms are the first organisms to have developed excretory organs (flame cells).

3. **Looking at Annelids**:
- Annelids, such as earthworms, have a more advanced excretory system that includes structures called nephridia. This indicates a higher level of complexity compared to flatworms.
- **Conclusion**: Annelids have excretory organs, but they are not the first to develop them.

4. **Considering Insects**:
- Insects possess excretory structures like Malpighian tubules and green glands, which are even more advanced than those found in annelids and flatworms.
- **Conclusion**: Insects have developed excretory organs, but they are not the first.

5. **Final Answer**:
- Based on the analysis, the first excretory organs were developed in flatworms, specifically in the form of flame cells.

### Final Answer:
The first time excretory organs were developed in flatworms.

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