Answer:
A. Atoms randomly crashing into each other
E. The force of one object pushing against the force of another object.
Explanation:
Forces can be classified into two categories based upon the the mode of transfer or application:
1. Contact forces
2. Non-contact forces
Contact forces are the ones which require the physical contact of the matter to get transferred and tend to create the affect. Whereas non-contact forces have the field property which transfers the affect of force from one point to another without any physical contact of the matter or the medium.