In a certain area, mosquitoes that can resist the effects of pesticides (insect-killing chemicals) now exist in greater numbers than10 years ago. What is the most probable explanation for this increase in numbers?

Select one:

Mosquito eggs were most likely to have been fertilized when exposed to the pesticides.


The pesticides acted as a repoductive hormone for previous generations of mosquitoes.


The pesticides serve as a new source of nutrition.


Genetic differences permitted some mosquitoes to survive the use of the pesticides.