meiosis migration immune responses gene mutations
I gave my students this multiple choice question: When the pesticide DDT was first used, it killed nearly every mosquito it touched. Within a few years, however, many mosquitoes became resistant to DDT and survived. What enabled this to happen?

Only one answer is correct among these 4 choices:
- meiosis
- migration
- immune responses
- gene mutations

Could you tell me which one is correct?

gene mutations