There is a theory that gravity could pull galaxies back together, causing a reverse big bang.

Which of the following is not am example of a polymer? protein nylon kevlar concreta

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

How do you tell if someone actually cares about you? and just say they do?