Answer:
Identical twins have a more similar personality than non-identical twins.
Identical twins who were raised in separate environments have a more similar personality than non-identical twins who were raised in the same environment.
Step-by-step explanation:
As you may already know, much has been discussed about the degree of influence that biological factors and environmental factors have on our personality. Although many scientists believe that environmental factors have a greater, and sometimes exclusive, influence on our personality, many scientific researches claim that biological factors have a greater influence. This is because these researches, through experiments, have obtained data that prove that identical twins (and that they have almost all biological factors equal) have very similar personalities, even though they were created in different environments. This similarity is so great that identical twins raised in different environments have a more similar personality than non-identical twins raised in the same environment.