No! It is not correct to say that evolution or gravity is JUST a theory!
You have to first know what a theory is!
A theory is generalized thought about something. NOT PROVEN!
Therefore a theory is not a fact!
So gravity is a fact. We can all prove that gravity exists
By simply jumping! We fall right back to the ground because gravity pulls us right back down! But space is a whole other story!
Evolution is the change through time! Proven scientifically with evidence of showing how things evolved!