Polar bodies

Options

A. have no know function
B. protect the egg
C. protect the sperm
D. ensure fertilisation

Answer

### Step-by-Step Solution:

1. **Understanding Polar Bodies**: Polar bodies are small cells that are produced during the process of oogenesis (the formation of egg cells) in females. They are formed alongside the egg cell but do not develop into viable eggs.

2. **Identifying Functions**: The primary function of polar bodies is often misunderstood. They do not play a direct role in fertilization or in protecting sperm. Instead, they serve to discard the extra genetic material that results from the unequal division of the cytoplasm during meiosis.

3. **Evaluating Options**: The question provides several options regarding the function of polar bodies:
- **Option 1**: Have no known function.
- **Option 2**: Protect the egg.
- **Option 3**: Protect the sperm and ensure fertilization.
- **Option 4**: Found in the embryo sac.

4. **Analyzing Each Option**:
- **Option 1** is incorrect because polar bodies do have a function, which is to help in the reduction of chromosome number.
- **Option 2** is correct as polar bodies do protect the egg by ensuring that the egg retains the majority of the cytoplasm and nutrients.
- **Option 3** is incorrect because polar bodies do not protect sperm or ensure fertilization.
- **Option 4** is incorrect because polar bodies are not found in the embryo sac; they are related to the egg cell formation.

5. **Conclusion**: The correct answer is that polar bodies protect the egg by allowing the egg to maintain its cytoplasmic volume and nutrient content, which is crucial for its development post-fertilization.

### Final Answer:
Polar bodies protect the egg.