Which of the following statement is incorrect about Gymnosperms.

Options

A. Pollination takes places by air in gymnosperms.
B. They are heterosporous
C. Before and after fertiilization, ovules are not enclosed by any overy wall and remain exposed.
D. All Gymnosperm are dioecious without any exception.

Explanation

To determine which statement about gymnosperms is incorrect, let's analyze each statement one by one:

1. **Pollination takes place by air in gymnosperms.**
- This statement is true. Gymnosperms primarily rely on wind for pollination, making air the main pollinating agent.

2. **They are heterosporous.**
- This statement is also true. Gymnosperms produce two types of spores: microspores (male) and megaspores (female), which is characteristic of heterosporous plants.

3. **Before and after fertilization, the ovules are not enclosed by an ovary wall and remain exposed.**
- This statement is true as well. In gymnosperms, the ovules are indeed exposed and not enclosed by an ovary wall, which distinguishes them from angiosperms.

4. **All gymnosperms are dioecious without any exception.**
- This statement is incorrect. While some gymnosperms are dioecious (having male and female reproductive structures on separate individuals), not all gymnosperms fall into this category. Some gymnosperms are monoecious, meaning they have both male and female reproductive structures on the same individual.

### Conclusion:
The incorrect statement about gymnosperms is: **"All gymnosperms are dioecious without any exception."**