Hair like outgrowths of the cell membrane which work like oars are

Options

A. Cilia
B. Flagella
C. Fimbriae
D. Sex pili

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the name of the hair-like outgrowths of the cell membrane that function like oars.

2. **Analyzing the Options**: The options provided are:
- A) Cilia
- B) Flagella
- C) Fimbri
- D) Sex pili

3. **Defining Cilia and Flagella**:
- **Cilia**: These are short, hair-like structures that cover the surface of some cells. They move in a coordinated manner to propel the cell or move fluid around it, functioning like oars.
- **Flagella**: These are longer than cilia and usually occur singly or in pairs. They also help in cell movement but are not typically described as working like oars.

4. **Evaluating Fimbri and Sex Pili**:
- **Fimbri**: These are structures found on bacterial cells that help them adhere to surfaces. They do not function like oars.
- **Sex Pili**: These are involved in bacterial conjugation, allowing the transfer of genetic material between bacteria. They do not have a role in movement.

5. **Conclusion**: Since cilia are the structures that are hair-like and function like oars, the correct answer is **Cilia**.

### Final Answer:
**Cilia** are the hair-like outgrowths of the cell membrane that work like oars.

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