what change in a population would you expect to see if a selection pressure was against the traits of the dominant allele?

The change in population in the given condition would be an increase of true recessive traits in the population and there would be only a few individuals with dominant traits.

In case of selection pressure was against the dominant trait, then individuals of the population who have true recessive alleles would have an advantage over the heterozygous and dominant individuals of the population.

There would be very few individuals carrying its dominant genotype and it may eventually be extinct, however, it would be still dominant. The recessive trait would just become more prominent rather than becoming dominant.

Thus, the number of recessive traits would increase in population, and the number of dominant decrease to numbers.

Learn more about selection pressure:

link

Decrease occur in the population of dominant allele occurs.

Change in a population of dominant allele occurs if a selection pressure was against the traits of the dominant allele because the selection pressure is against the dominant allele that leads to appearance of recessive allele and disappearance of dominant allele. The selection pressure is responsible for the appearance of allele in the offspring so we can conclude that dominant allele is decreases in the population of the future generation.

link

c.more precipitation,but only when emission levels.