Identical twins, who have inherited a gene associated with obesity, are adopted by different families. One is growing up in a very health-conscious family, while the other is growing up in a family that eats a lot of fast food and never exercises. Which statement describes their likely weights upon reaching adulthood? A.
They will both be overweight because they both have the gene associated with obesity.

B.
They will both be of average weight because their genes will mutate as they grow and develop.

C.
The weight of the twins is difficult to predict because both genes and environmental factors affect weight.

D.
One twin will be overweight and the other will be of average weight, because they were raised in different environments.