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PLEASE HELP ME!!!!!!!!!!!!!!!!!!!!
In a certain area, mosquitoes that are resistant to the pesticide DDT now exist in greater numbers than 10 years ago. What is the best explanation for the increase in their numbers?

A
Genetic differences permitted some mosquitoes to become immune to DDT.

B
DDT was extremely harmful to the predators of mosquitoes.

C
DDT killed only the weak in the previous generations of mosquitoes.

D
Mosquito eggs were most likely to have been fertilized when exposed to DDT.