Answer:
The correct answers would be: Environmental influences on personality traits are most clearly highlighted by comparing identical twins who have been raised together with identical twins who have been raised in separate environments.
Step-by-step explanation:
One of the most common scientific observations that researchers have done regarding the way that the environment plays a role in the development of personality, is the one done on identical twins. This is because genetically, identical twins are, as the word means, identical in almost every respect. As it would be expected, it was theorized that both individuals should develop similar personalities, as their genes are almost the same. However, this theory was proved wrong when researchers started studying identical twins who had one of two conditions: they had been raised together, or apart. This proved to researchers that genetics does play a part in personality development, but environment, was also crucial, and it justified differences that were identified in sets of twins that were compared.