Question

an extensive study was conducted on identical twins who were separated at birth. among other things, the study showed that the individual from each pair who received better nutrition during childhood tended to score higher on standardized intelligence tests. this can best be described as an example of how
multiple choice
○ environment alters phenotype.
○ mutation alters phenotype.
○ mutation alters genotype.
○ environment alters genotype.
○ pleiotropic genes affect more than one trait.

Explanation:

Identical twins share identical genotypes. The difference in intelligence test scores (a phenotypic trait) is due to better nutrition (an environmental factor), showing environment affects phenotype. Mutation and pleiotropy are irrelevant here; environment does not alter genotype.

Answer:

environment alters phenotype.