Question

What evidence suggests that people's brains function in a relatively similar way?

Answer 1

I believe the answer is: D. when people thing about a specific emotion, their brains show similar patterns of activity

If a certain biological function happen to all people, we could infer that the function is influenced by genetics (it does not need to be learned in order to happen). Since the way we express our emotion often cannot be controlled, we can conclude the fact that people behave generally the same when facing  an emotion shows that people's brain functioned in a similar way.