Name the toxic protein secreted by Bacillus thuringiensis.

Explanation

**Step-by-Step Solution:**

1. **Identify the Organism**: The question asks about the toxic protein secreted by *Bacillus thuringiensis*. This is a type of bacteria that is known for its insecticidal properties.

2. **Understand the Characteristics**: *Bacillus thuringiensis* is a gram-positive, soil-dwelling bacterium. It is notable for being spore-forming, which means it can produce spores that help it survive in harsh conditions.

3. **Protein Production**: During the process of sporulation, *Bacillus thuringiensis* synthesizes certain proteins. One of the key types of proteins produced during this process is known as parasporal crystalline proteins.

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