Scientists studying a population of fruit flies observe that a small percentage of the population mates in the morning while the rest of the population mates at night. Scientists predict that over time the population that mates in the morning and the populations that mates at night will become different species. Which of the following best supports the scientists prediction that speciation will occur in the fruit fly population?
a. There will be fewer offspring produced in the population of fruit flies that mates in the morning than in the population that mates at night.
b. There will be structural differences in the reproductive organs of the fruit flies in the populations that mates in the morning and those of the fruit flies in the population that mates at night.
c. There will be increasing geographic isolation between the population of fruit flies that mates in the morning and the population of fruit flies that mates at night.
d. There will be an accumulation of genetic differences between the population of fruit flies that mates in the morning and the population of fruit flies that mates at night.​