Why is the gene coding for Bt toxin called 'cry'?

Explanation

### Step-by-Step Solution:

1. **Understanding Bt Toxin**:
- Bt toxin is an endotoxin produced by the bacterium *Bacillus thuringiensis*. It is known for its ability to kill certain insects and pests.

2. **Function of Bt Toxin**:
- The primary function of Bt toxin is to act as an insecticide. It is used in agriculture to protect crops from insect damage.

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