The crops having cry-genes need-
a) No insecticide
b) Mild quantity of insecticide
c) Large amount of insecticide
d) 5 kg insecticide/hectare

Options

A. No insecticide
B. Mild quantity of insecticide
C. Large amount of insecticide
D. 5 kg insecticide/hectare

Answer

To answer the question regarding the need for insecticides in crops that have cry-genes, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cry-genes**: Cry-genes, specifically the cry protein from Bacillus thuringiensis (Bt), are genes that provide resistance to certain insects. These genes are often inserted into genetically modified (GM) crops.

2. **Function of Cry-proteins**: The cry proteins, when ingested by insects, become active in the alkaline environment of the insect's digestive system. This activation leads to the formation of toxic proteins that damage the insect's gut, ultimately resulting in the insect's death.

3. **Impact on Insecticide Use**: Since these GM crops produce their own insecticidal proteins, they are inherently resistant to insect pests. This means that the crops do not require additional chemical insecticides to protect them from insect damage.

4. **Conclusion**: Given that crops with cry-genes can effectively defend themselves against pests, the correct answer to the question is that they need **no insecticide**.

### Final Answer:
**a) No insecticide**

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