What is the best kind of boundary between states (countries)

Explain the popular saying "we are made of stardust. how are we made of stardust? use scientific vocab.

Melissa is fearful of men and refuses to go on dates. her therapist suggests that she is fearful because she was sexually abused when she was young. the therapist's suggestion most clearly reflects a perspective. a.) humanistic b.) behavioralc.) biological d.) psychoanalytice.) sociocultural

This is an ap world history question. i am working on a worksheet which has a vent diagram with each circle labeled either us or byzantine economy. the middle is the similarities. can someone explain to me the similarities and especially the differences between the two?