Assertion: Bacillus thuringiensis is not killed by its own toxin
Reason :Bt toxin protein exist as inactive protoxins

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion
B. It both Assertion & Reason are True but Reason is not a correct explanation of the Assetion
C. If Assertion is True but the Reason is False
D. If both Assertion & Reason are false

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "Bacillus thuringiensis is not killed by its own toxin." This means that the bacterium can produce a toxin without being harmed by it.

2. **Understanding the Reason:**
- The reason provided is that "Bt toxin protein exists as inactive protoxins." This indicates that the toxin is produced in an inactive form, which is not harmful to the bacterium itself.

3. **Mechanism of Action:**
- When Bacillus thuringiensis (Bt) is ingested by an insect, the alkaline environment of the insect's gut activates the inactive protoxin, converting it into an active toxin.

4. **Effect of the Toxin:**
- The activated toxin then forms pores in the gut of the insect, leading to the insect's death. This is a mechanism of pest control used in agriculture.

5. **Conclusion:**
- Since the assertion is true (Bacillus thuringiensis is not harmed by its own toxin) and the reason is also true (the toxin exists as inactive protoxins), and the reason correctly explains the assertion, we conclude that both the assertion and reason are true and the reason is the correct explanation for the assertion.

**Final Answer:**
Both assertion and reason are true, and the reason is the correct explanation of the assertion.

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