Select the mismatch

Options

A. cry I Ac – Helicoverpa
B. cry I Ab – Com borer
C. cry II Ab – Corn borer
D. cry I Ab – Ostrinia

Answer

To solve the question of selecting the mismatch among the given options related to disease-resistant genes and their corresponding pests, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Cry 1AC**:
- Cry 1AC is a gene that produces a Bt toxin, which is effective against the pest Helicoverpa (commonly known as the cotton bollworm).
- This option is correctly matched.

2. **Understanding Cry 1AB**:
- Cry 1AB is another Bt toxin gene that is effective against the corn borer.
- This option is also correctly matched.

3. **Understanding Cry 2AB**:
- Cry 2AB is mentioned to be associated with the corn borer. However, it is actually effective against cotton bollworms, not corn borers.
- This option is mismatched.

4. **Understanding Cry 1AB (again)**:
- The mention of Cry 1AB being related to Austrinia (which seems to be a typographical error for "Austrian" or "Austria") is not relevant to the pest association but is still a toxin-producing gene.
- This option is correctly matched in terms of its function.

### Conclusion:
- The third option, Cry 2AB, is the mismatch because it is incorrectly associated with the corn borer when it actually targets cotton bollworms.

### Final Answer:
**The mismatch is Cry 2AB with corn borer.**

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