While dancing at a club, darryl didn't realize how crowded the dance floor had become till he started to notice that he couldn't move his arms without hitting someone dancing beside him. this is an example of which type of factor that influences our perception of crowding?

I believe the correct answer is behavioral constraint.
According to the theory of behavioral constraint, there is a certain factor which prevents us from achieving our desired behavior. In this case, Darryl wants to dance without having to hit people dancing around him, but he cannot do it because the club is crowded. 

The answer would be limited.

The answer would be political systems .