What is cry protein?

Explanation

### Step-by-Step Solution:

1. **Definition of Cry Protein**: Cry proteins are a large family of crystalline toxins that are produced by certain bacteria.

2. **Source of Cry Protein**: The primary bacterium that produces these cry proteins is called *Bacillus thuringiensis*, often abbreviated as Bt.

3. **Nature of Cry Protein**: These proteins are toxic in nature, specifically targeting insects.

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