What is the real mechanism of gravity Holding the Universe as a Structure?

Answer 1

At present I believe the scientists have to identify the "dark matter" content of the universe and understand it in order to answer your complete question.

Answer 2

I think that "dark matter" doesn't hold universe together! It helps expansion and accelerates it! In fact we don't know how gravity works since we can observe only a small fragment of "matter". The known matter as we have experienced it is only the 4% of the known universe! This has recently discovered!

Answer 3

We do not have sufficient knowledge of gravity to say what it is.