Final answer:
Identical twins separated at birth are most likely to have similar personalities, as shown by the Minnesota Study of Twins Reared Apart, which indicates that certain personality traits have strong hereditary components.
Step-by-step explanation:
The question asks which trait identical twins separated at birth are most likely to have in common, choosing from political ideas, religious beliefs, personality, norms, or food preferences. According to the Minnesota Study of Twins Reared Apart, identical twins, whether raised together or apart, have very similar personalities.
While factors such as religious beliefs and political ideas are significantly influenced by the environment in which a child is raised, research in the field of behavioral genetics shows that personality traits have a strong hereditary component. The Minnesota study found that traits such as leadership, obedience to authority, a sense of well-being, alienation, resistance to stress, and fearfulness have a heritability ratio of more than 0.50, indicating a substantial genetic influence on these aspects of personality.