Bt cotton is resistant to

Options

A. Insects
B. Herbicides
C. Salt
D. Drought

Answer

**Step-by-Step Solution:**

1. **Understanding Bt Cotton**: Bt cotton is a genetically modified organism (GMO) that has been engineered to express a specific protein from the bacterium Bacillus thuringiensis (Bt).

2. **Source of Resistance**: The resistance in Bt cotton comes from the insertion of the Bt toxin gene into the cotton plant. This gene enables the plant to produce proteins known as cryoproteins.

3. **Mechanism of Action**: When insects, particularly caterpillars, feed on the Bt cotton, the cryoproteins are activated in the alkaline environment of the insect's gut.

4. **Effect on Insects**: The activated cryoproteins damage the epithelial cells of the insect's midgut, leading to cellular swelling, lysis (breaking down of cells), and ultimately the death of the insect.

5. **Conclusion**: Therefore, Bt cotton is primarily resistant to certain insects, especially caterpillars, due to the insecticidal properties of the cryoproteins produced by the plant.

**Final Answer**: Bt cotton is resistant to insects, mainly caterpillars.

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