Both, autogamy and geitonogamy are prevented in

Options

A. Papaya
B. cucumber
C. castor
D. maize

Answer

To solve the question "Both autogamy and geitonogamy are prevented in which of the following options: papaya, cucumber, oyster, and maize?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Autogamy**: This is a type of self-pollination where pollen from the anther of a flower fertilizes the stigma of the same flower.
- **Geitonogamy**: This is another form of self-pollination where pollen from one flower fertilizes the stigma of another flower on the same plant.

2. **Identify Plant Types**:
- **Dioecious Plants**: These are plants that have male and female reproductive organs on separate individuals. This means that for fertilization to occur, pollen must be transferred from a male plant to a female plant, preventing both autogamy and geitonogamy.
- **Monoecious Plants**: These have both male and female organs in the same plant, allowing for both autogamy and geitonogamy.

3. **Analyze the Options**:
- **Papaya**: This is a dioecious plant, meaning it has separate male and female plants. Therefore, both autogamy and geitonogamy are prevented.
- **Cucumber**: This is a monoecious plant that can undergo both self-pollination (autogamy) and geitonogamy.
- **Oyster**: This is not a flowering plant, and the context of pollination does not apply here.
- **Maize**: This is also a monoecious plant, allowing for both self-pollination and cross-pollination.

4. **Conclusion**:
- The only plant from the options that prevents both autogamy and geitonogamy is **Papaya**.

### Final Answer:
Both autogamy and geitonogamy are prevented in **Papaya**.

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