DrCho Wants to Know If Differences in the Growth Rate

Dr.Cho wants to know if differences in the growth rate of fish are based on genetics or the environment.He buys two fish.Fish 1 is fed everyday,while fish 2 is fed every other day.At the end of a month,fish 1 is nearly 15 percent larger than fish 2.Considering the fish have nearly identical genetic makeup,what can Dr.Cho conclude?

A) Environmental changes can account for all the differences in growth rate.
B) Genetic influences must account for a majority of the differences in growth rate.
C) Environmental conditions were more favorable for fish 2.
D) Differences in growth rate cannot be determined by his simple experiment.