Find the correct statement for the prothallus of fern.

Options

A. Monoecious , protandrous with multicellular rhizoides
B. Monoecious , protandrous with unicellular rhizoides
C. Dioecious , with unicellular rhizoides
D. Monoecious , protandrous with apical antheredia and basal archegonia on ventral surface

Answer

To find the correct statement for the prothallus of fern, we need to analyze the options provided based on our understanding of fern biology.

### Step-by-Step Solution:

1. **Understanding Prothallus**:
- The prothallus is the gametophyte stage of ferns, which is a small, heart-shaped structure that develops from the spore. It is responsible for producing gametes (sperm and eggs).

2. **Identifying Key Terms**:
- **Monoecious**: This means that both male and female reproductive organs are present on the same individual.
- **Dioecious**: This means that male and female reproductive organs are on separate individuals.
- **Protoandrous**: This term indicates that the male gametes mature before the female gametes.
- **Rhizoids**: These are root-like structures that anchor the prothallus; they can be unicellular or multicellular.

3. **Analyzing the Options**:
- **Option 1**: Monoecious protoandrous with multicellular rhizoids.
- **Option 2**: Monoecious protoandrous with unicellular rhizoids.
- **Option 3**: Dioecious with unicellular rhizoids.
- **Option 4**: Monoecious protoandrous with apical antheridia and basal archegonia on the ventral surface.

4. **Evaluating Each Option**:
- **Option 1**: While it is monoecious and protoandrous, ferns typically have unicellular rhizoids.
- **Option 2**: This correctly states that the prothallus is monoecious and protoandrous, and it mentions unicellular rhizoids, which is accurate for ferns.
- **Option 3**: This is incorrect because ferns are not dioecious.
- **Option 4**: While it mentions the correct arrangement of reproductive organs, it does not specify the type of rhizoids accurately.

5. **Conclusion**:
- The correct statement for the prothallus of fern is **Option 2**: Monoecious protoandrous with unicellular rhizoids.