Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because

Options

A. Bacteria are resistant to the toxin
B. Toxin is immature
C. Toxin is inactive
D. Bacteria encloses toxin in a special sac

Answer

**Step-by-Step Solution:**

1. **Understanding Bt Toxin**: The question revolves around the Bt toxin, which is produced by the bacterium Bacillus thuringiensis. It is important to recognize that this toxin is specifically designed to target certain insects.

2. **Nature of the Toxin**: The Bt toxin is produced in an inactive form known as a protoxin. This means that while the bacteria can produce the toxin, it does not have the ability to harm itself because the toxin is not active in its original state.

3. **Activation of the Toxin**: The inactive protoxin becomes active only when it enters the gut of an insect. In the insect's digestive system, the protoxin is converted into the active form of the toxin, which can then exert its harmful effects on the insect.

4. **Analyzing the Options**:
- **Option A**: "Bacteria resistance to the toxin" - This is incorrect because the bacteria does not need to be resistant; it simply does not produce an active toxin.
- **Option B**: "Toxin is immature" - This is also incorrect; the term "immature" does not accurately describe the inactive protoxin.
- **Option C**: "Toxin is inactive" - This is the correct option. The Bt toxin is produced in an inactive form, which prevents it from harming the bacteria itself.
- **Option D**: "Bacteria encloses toxin in a special sack" - This is incorrect; there is no special sack involved in the storage of the toxin.

5. **Conclusion**: The correct answer to the question is **Option C: Toxin is inactive**. This explains why the crystals of Bt toxin do not kill the bacteria that produce them.

---