Daiyo, a behavioral geneticist, is studying the interaction of heredity and environment. When he looks at monozygotic twins, what will he probably see in their phenotypes?

Their genotypes will predispose them towards certain traits but their environment influence weather those traits are expressed in their phenotypes

Explanation:

All traits depend both on genetic and environmental factors. Hereditary and environment interact to produce their effects. this means that the way genes act depends on the environment in which they are act. In the same way effect of the environment depends on the genes which they work. for example people vary in heights. Although Height is highly heritable, environmental variables can have a large impact for example, Japanese Americans are on the average heavier and taller than their second cousins which grew up in Japan reflecting the effect of environmental variables especially dietary difference.

not sure if this what   you'r looking for would be percent composition