Contrivance for self pollination is

Options

A. Cleistogamy
B. Bisexuality
C. Homogamy
D. All the above.

Answer

To solve the question "Contrivance for self-pollination is", we need to analyze the options provided: clistogamy, bisexuality, homogamy, and all the above.

### Step-by-Step Solution:

1. **Understanding Self-Pollination**:
- Self-pollination is the process where pollen from the male part of a flower fertilizes the female part of the same flower or another flower on the same plant. This is in contrast to cross-pollination, where pollen is transferred between different plants.

2. **Identifying the Contrivances**:
- **Clistogamy**: This refers to a type of flower that does not open and thus ensures self-pollination. These flowers are typically closed and only allow for self-pollination.
- **Bisexuality**: This means that the flower contains both male (stamens) and female (pistils) reproductive organs. This allows for self-fertilization as both gametes are present in the same flower.
- **Homogamy**: This refers to the condition where the male and female reproductive organs mature at the same time, facilitating self-pollination.

3. **Evaluating the Options**:
- All three terms—clistogamy, bisexuality, and homogamy—describe mechanisms or adaptations that promote self-pollination.
- Therefore, the correct answer must include all these mechanisms.

4. **Conclusion**:
- Since all the mentioned options contribute to the process of self-pollination, the correct answer is **all the above**.

### Final Answer:
The contrivance for self-pollination is **all the above** (clistogamy, bisexuality, homogamy).