Define vernalisation.

Explanation

### Step-by-Step Solution:

1. **Definition of Vernalisation**: Vernalisation is the process of inducing flowering in plants by exposing them to a period of cold temperatures.

2. **Purpose of Vernalisation**: The main purpose of vernalisation is to stimulate the flowering process in plants that require a period of cold to trigger this developmental stage.

3. **Temperature Range**: The cold treatment typically involves temperatures ranging from 0 degrees to 5 degrees Celsius.

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