Why do insect pests become resistant so readily to the pesticides used for control?

A.Insects reproduce in large numbers, increasing the chances of mutations that contribute to resistance.
B.An effective way to reduce pesticide resistance is to develop new pesticides.
C.Mutation in only a single gene can lead to the evolution of a resistant organism.
D.Insect exoskeletons reduce the effectiveness of pesticides and the death rate is much lower than was ever expected.
E.We often rely almost exclusively on pesticides for pest control and this increases selection pressure towards resistance.
F.Because insects have a short life span, they can produce many generations of offspring in a relatively short period.

More than one answer help plz