Which one is correct about heterosporous pteridophytes?

Options

A. microspore and megaspores develop into the male and the female gametophytes respectively
B. The female gametophyte are retained on the parent sporophyte for variable period
C. The development of the zygote into the embryo takes place within female gametophyte,
D. All

Answer

To answer the question about heterosporous pteridophytes, we will break down the information step by step.

### Step-by-Step Solution:

1. **Understanding Heterosporous Pteridophytes**:
- Heterosporous pteridophytes are a specific group of pteridophytes that produce two different types of spores: microspores and megaspores.
- Microspores are small and develop into male gametophytes, while megaspores are larger and develop into female gametophytes.

2. **Characteristics of Spores**:
- In heterosporous pteridophytes, the microspores and megaspores are produced in different structures. The microspores are produced in microsporangia, and the megaspores are produced in megasporangia.

3. **Development of Gametophytes**:
- The microspores develop into male gametophytes, which are responsible for producing sperm.
- The megaspores develop into female gametophytes, which produce eggs.

4. **Retention of Female Gametophyte**:
- In heterosporous pteridophytes, the female gametophyte (developed from the megaspore) is retained on the parent sporophyte for varying periods. This retention allows for better protection and nourishment of the developing gametophyte.

5. **Zygote Development**:
- After fertilization, the zygote develops into an embryo within the female gametophyte. This is a significant evolutionary step as it indicates a precursor to seed formation.

6. **Conclusion**:
- All the statements provided in the question about heterosporous pteridophytes are correct:
1. Microspore and megaspore develop into male and female gametophytes, respectively.
2. The female gametophyte is retained on the parent sporophyte for a variable period.
3. The zygote develops into an embryo within the female gametophyte.

### Final Answer:
All statements regarding heterosporous pteridophytes are correct.

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