The bacterum Bacillus thuringiensis is widely used in contemporary biology as

Options

A. Bioweapon
B. Bioinsecticide
C. Bioweedicide
D. Indicator of water pollution

Answer

**Step-by-Step Solution:**

1. **Identify the Bacterium**: The bacterium in question is Bacillus thuringiensis (Bt). It is a type of bacteria that is known for its insecticidal properties.

2. **Understand the Function**: Bacillus thuringiensis produces a specific toxin known as the Bt toxin or endotoxin. This toxin is effective against certain insects.

3. **Mechanism of Action**: The Bt toxin is produced in an inactive form within the bacterium. When an insect ingests Bacillus thuringiensis, the toxin becomes active in the insect's gut.

4. **Effect on Insects**: Once activated, the Bt toxin disrupts the gut of the insect, leading to its death. This makes Bacillus thuringiensis a natural insecticide.

5. **Classification**: Since it is a microorganism used to control insect populations, Bacillus thuringiensis is classified as a bio insecticide.

6. **Evaluate Other Options**:
- **Bioweapon**: This refers to microorganisms used intentionally to cause harm, which does not apply to Bacillus thuringiensis.
- **Biomedicide**: This term is not commonly used in relation to Bacillus thuringiensis.
- **Indicator of Water Pollution**: Bacillus thuringiensis does not serve this function as it targets insects, not water quality.

7. **Conclusion**: The correct classification of Bacillus thuringiensis in contemporary biology is as a bio insecticide.

**Final Answer**: Bacillus thuringiensis is widely used in contemporary biology as a bio insecticide.

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