A unisexual flowering plant containing either only staminate or only pistillate flowers prevents both

Options

A. Autogamy and xenogamy
B. Autogamy and geitonogamy
C. Geitonogamy and xenogamy
D. Cleistogamy and xenogamy

Explanation

To solve the question regarding a unisexual flowering plant that contains either only staminate (male) or only pistillate (female) flowers, we need to analyze the types of pollination and determine which ones would be prevented.

### Step-by-Step Solution:

1. **Understanding Unisexual Flowers**:
- A unisexual flowering plant has either staminate (male) flowers or pistillate (female) flowers, but not both. This means that one type of reproductive structure is absent.

2. **Types of Pollination**:
- **Autogamy**: This is self-pollination that occurs within the same flower. Since unisexual flowers lack both male and female parts, autogamy cannot occur in these plants.
- **Xenogamy**: This is cross-pollination between different plants. Since a unisexual plant can still have male and female plants, xenogamy can occur if a male plant pollinates a female plant.
- **Gytogamy**: This refers to pollination between two flowers of the same plant. Since a unisexual plant only has either male or female flowers, gytogamy cannot occur.

3. **Conclusion**:
- Since autogamy and gytogamy both require the presence of both male and female reproductive structures (which are absent in unisexual plants), both types of pollination will be prevented.
- Xenogamy, on the other hand, can still occur between different unisexual plants (one male and one female).

Therefore, the types of pollination that are prevented in a unisexual flowering plant containing either only staminate or only pistillate flowers are **autogamy and gytogamy**.

### Final Answer:
The correct answer is that a unisexual flowering plant prevents **autogamy and gytogamy**.

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