The trigger for activation of toxin of Bacillus thuringiensis is

Options

A. acidic pH of stomach
B. high temperature
C. alkaline pH of gut
D. mechanical action in the insect gut

Explanation

**Step-by-Step Solution:**

1. **Understanding Bacillus thuringiensis (Bt):**
- Bacillus thuringiensis is a bacterium that produces a toxin known as Bt toxin, which is used as a biological pesticide.

2. **Nature of the Toxin:**
- The toxin produced by Bacillus thuringiensis is initially in an inactive form known as a protoxin.

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