Which of the following statements is correct ?

Options

A. a) Ovules are not enclosed by ovary wall in gymnosperms
B. b) Selaginella is heterosporous, while Salvinia is homosporous
C. c) Horsetails are gymnosperms
D. d) Stems are usually unbranched in both Cycas and Cedrus

Answer

To solve the question "Which of the following statements is correct?", we will analyze each of the given options one by one.

### Step-by-Step Solution:

1. **Option A: Ovules are not enclosed by ovary wall in gymnosperm.**
- In gymnosperms, ovules are indeed not enclosed by an ovary wall. Instead, they are exposed on the surface of the cone scales. This statement is correct.

2. **Option B: Selaginella is heterosporous while Salvinella is homosporous.**
- Selaginella is known to be heterosporous, meaning it produces two types of spores (microspores and megaspores). However, Salvinella is also heterosporous, not homosporous. Therefore, this statement is incorrect.

3. **Option C: Horsetails are gymnosperm.**
- Horsetails belong to the group of Pteridophytes, which are seedless vascular plants. They are not gymnosperms. Hence, this statement is incorrect.

4. **Option D: Stems are usually unbranched in both Cycas and Cedrus.**
- In Cycas, the stem is typically unbranched, but in Cedrus (a type of pine), the stems are branched. Therefore, this statement is also incorrect.

### Conclusion:
After analyzing all the options, the only correct statement is **Option A: Ovules are not enclosed by ovary wall in gymnosperm**.

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