What is the most appropriate reason for the survival of bacteria Bacillus thruringiensis inspite of having Bt toxin in it?

Options

A. Toxin is present in inactive stage
B. Bacterial cell resistance
C. Plasmid action
D. Transcription

Answer

### Step-by-Step Solution:

1. **Understanding Bacillus thuringiensis (Bt)**: Bacillus thuringiensis is a bacterium known for producing a toxin that is harmful to certain insects. This toxin is often used in agriculture as a biological pesticide.

2. **Nature of Bt Toxin**: The toxin produced by Bacillus thuringiensis is initially formed as protein crystals. These crystals are in an inactive form, often referred to as protoxins.

3. **Activation of the Toxin**: When these inactive protein crystals enter the gut of an insect, they encounter an alkaline environment (with a pH around 10). This specific pH triggers the conversion of the inactive protoxin into its active form.

4. **Survival Mechanism**: The key to the survival of Bacillus thuringiensis despite producing the Bt toxin lies in the fact that the toxin remains inactive while inside the bacterial cells. This means that the bacterium can survive and reproduce without being harmed by its own toxin.

5. **Conclusion**: Therefore, the most appropriate reason for the survival of Bacillus thuringiensis in spite of having Bt toxin is that the toxin is present in an inactive stage within the bacterial cells.

### Final Answer:
The most appropriate reason for the survival of Bacillus thuringiensis despite having Bt toxin in it is that the toxin is present in an inactive stage.

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