Family studies can indicate whether a trait runs in families, but they cannot provide conclusive evidence that a trait is influenced by heredity because
A)there are too many dependent variables in family studies.
B)random assignment is impossible in family studies.
C)there are no independent variables in family studies.
D)family members share not only genes but also similar environments.

Question

Family studies can indicate whether a trait runs in families, but they cannot provide conclusive evidence that a trait is influenced by heredity because ​
A)there are too many dependent variables in family studies.
B)random assignment is impossible in family studies.
C)there are no independent variables in family studies.
D)family members share not only genes but also similar environments.

Quizplus · Accepted Answer

Family studies can show that a trait appears in a family lineage, but they cannot definitively prove that the trait is genetic because family members also share similar environments, which can influence the presence of the trait.

Family Studies Can Indicate Whether a Trait Runs in Families