Which characteristics of abstract expressionism did pop artists rebel against? Also, how did pop art differ from abstract expression?

Pop Art is a style of art which explores the everyday imagery that is so much a part of contemporary consumer culture. Common sources of imagery include advertisements, consumer product packaging, celebrity photographs, and comic strips.

That means subjects. Abstract paintings by definition have no subjects.

It isn't so much a rebellion against Abstract Expressionism ; it's just to take art in a new direction in order to be noticed.

hope this helps

plz