Which one of the following is homosporous with exo- scopic embryogeny?

Options

A. All pteridophytes
B. Bryophytes and gymnosperms
C. Angiosperms
D. All bryophytes

Answer

To determine which of the following is homosporous with exoscopic embryogeny, we need to analyze the definitions and characteristics of the given options.

### Step-by-Step Solution:

1. **Understand the Terms:**
- **Homosporous:** This refers to plants that produce only one type of spore, which is uniform in size and shape. This means all spores are identical.
- **Exoscopic Embryogeny:** This is a type of embryonic development where the zygote divides to form two cells, and the outer cell (exoscopic) develops into the embryo.

2. **Analyze the Options:**
- **All Pteridophytes:** Pteridophytes can be either homosporous or heterosporous. Therefore, this option is not correct.
- **Bryophytes and Gymnosperms:** Bryophytes are generally homosporous, but gymnosperms are typically heterosporous. Thus, this option is incorrect.
- **Angiosperms:** Angiosperms are known to be heterosporous, producing two types of spores (male and female). Hence, this option is also incorrect.
- **All Bryophytes:** Bryophytes are indeed homosporous and exhibit exoscopic embryogeny, making this option the correct answer.

3. **Conclusion:**
- The only group that is both homosporous and exhibits exoscopic embryogeny is **All Bryophytes**.

### Final Answer:
**All Bryophytes**