Seen through a traditional optical telescope, the space between stars and galaxies is pitch black. but, with a radio telescope, we detect a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. this phenomenon, which provides evidence for the big bang theory, is called the a) redshift. b) singularity. c) universal field theory. d) cosmic microwave background.

That's the Cosmic Microwave Background (CMB). (D)

It doesn't "provide evidence for the ... Theory". The Big Bang theory is the best explanation (so far) for the CMB and a lot of other observations.

Evidence isn't used to prove theories. Theories are attempts to explain evidence.

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.