Microevolution, or evolution at its smallest scale, occurs when
a) an individual's traits change in response to environmental factors.
b) a community of organisms changes due to the extinction of several dominant species.
c) a new species arises from an existing species.
d) a population's allele frequencies change over a span of generations.
e) none of the above.

D) a population's allele frequencies change over a span of generations.

Explanation:

Microevolution occurs within a population whereby gene flow, mutation, genetic drift or natural section brings about a change in a population’s allele frequencies over several generations. It occurs on a small scale. Examples of microevolution can be observed in resistance being evolved by pests to pesticides. i.e. Mosquitoes developing resistance against DDT. Mosquitoes with genes that can withstand DDT have evolved overtime.

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.

well the answer is 2!