Twin and adoption studies have been most helpful for teasing apart the influences of

A) genetic mutations and epigenetic marks.
B) extraversion and neuroticism.
C) genes and protein molecules.
D) heredity and environment.

Twin and adoption studies have been most helpful for teasing apart the influences of heredity and environment. By studying the similarities and differences between identical twins who share 100% of their genes and fraternal twins who share around 50% of their genes, researchers can determine the degree to which genetic factors contribute to various traits and behaviors. Similarly, adoption studies allow researchers to compare adopted children to their biological and adoptive parents, allowing for an exploration of the role of environment and upbringing on various outcomes.