Why does it take a long time to develop a new variety of tomato?
a. changes in traits happen gradually, over many generations.
b. tomatoes cannot acquire new traits.
c. a species cannot change over time.
d. many plants resist change.

not the best question format lol but what i think might as scale color is controlled by a single gene with two alleles, the green allele and the yellow allele. when moths that are homozygous for green scales are mated with moths that are homozygous for yellow scales, 100% of the offspring have green scales.