Biennials get changed into annuals by

Options

A. hormones
B. photoperiodism
C. grafting
D. vernalization

Answer

To solve the question "Biennials get changed into annuals by," we will analyze the options provided and determine which one is correct based on biological principles.

### Step-by-Step Solution:

1. **Understanding Biennials and Annuals**:
- Biennials are plants that take two years to complete their life cycle, typically flowering in the second year.
- Annuals are plants that complete their life cycle in one year, flowering and dying within the same growing season.

2. **Analyzing the Options**:
- **Hormones**: While hormones do play a significant role in plant growth and development, they do not specifically convert biennials into annuals.
- **Photoperiodism**: This refers to how plants respond to the length of day and night, influencing flowering and growth. However, it does not directly change the classification of a plant from biennial to annual.
- **Grafting**: This is a horticultural technique where tissues from one plant are inserted into another. It does not change the life cycle of a biennial plant to that of an annual.
- **Vernalization**: This is the process of inducing flowering in plants by exposing them to prolonged cold or low temperatures. This process is particularly important for biennial plants, as it can trigger them to flower in their first year, effectively changing their life cycle to that of an annual.

3. **Conclusion**:
- The correct answer is **vernalization**. This process allows biennial plants to flower earlier, thus behaving like annuals.

### Final Answer:
Biennials get changed into annuals by **vernalization**.

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