Question

based on the information, which evidence best supports the idea that exposure to ddt led to natural selection?
a. the proportion of bedbugs that were resistant to ddt increased.
b. the use of ddt occurred over many generations of bedbugs.
c. bedbugs developed mutations that increased their susceptibility to ddt.
d. many bedbug infestations from the 1950s to the 1970s were treated with ddt.

Explanation:

Natural selection is the process by which organisms with favorable traits are more likely to survive and reproduce. In the context of bedbugs and DDT, if the proportion of bedbugs resistant to DDT increased, it means that the resistant - bedbugs had a survival advantage over non - resistant ones when exposed to DDT, which is evidence of natural selection. Option B only mentions the time - span of DDT use, not a change in the bedbug population related to survival. Option C describes mutations that increase susceptibility, which is contrary to the idea of natural selection leading to resistance. Option D just states the use of DDT for bedbug infestations, without showing any change in the bedbug population due to DDT exposure.

Answer:

A. The proportion of bedbugs that were resistant to DDT increased.