Question

twin and adoption studies have been most helpful for teasing apart the influences of
a genetic mutations and epigenetic marks.
b extraversion and agreeableness.
c genes and protein molecules.
d genes and environment.

Explanation:

Twin and adoption studies are used to distinguish between genetic and environmental influences. Identical twins share the same genes, and differences between them can often be attributed to environmental factors. Adoption studies compare adopted - children to their biological and adoptive parents to separate genetic and environmental impacts.

Answer:

D. Genes and environment.