Excretory structures in adult Ascaris are

Options

A. renette cells
B. excretory canals
C. Nephridia
D. malpighian tubules

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the excretory structures found in adult Ascaris, which is a type of parasitic roundworm.

2. **Identifying Excretory Structures**: Ascaris has a simple excretory system. It is important to note that it does not have a complex structure like flame cells or protonephridia, which are found in some other organisms.

3. **Describing the Excretory System**: The excretory system of Ascaris consists of a single giant H-shaped cell known as a "renit cell." This structure is responsible for the excretion process in adult Ascaris.

4. **Evaluating the Options**: The options given are:
- A. Renit cells
- B. Excretory canals
- C. Nephridia
- D. Malpighian tubules

Based on the information about Ascaris, we can eliminate options B, C, and D, as they do not correspond to the excretory structures present in Ascaris.

5. **Conclusion**: The correct answer is option A, which states that the excretory structures in adult Ascaris are renit cells.

### Final Answer:
The excretory structures in adult Ascaris are **renit cells** (Option A).

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