It would be the universe since
the universe refers to the whole world!
No.
The word "universe" means "all space, all time, and everything in them". It's the concept that includes everything, and bigger than which nothing is.
No the Milky Way is only a galaxy in space (the Universe) and is very small indeed by comparison.
A universe is bigger than an organism.
A universe is bigger than a planet.
the universe is bigger
the universe is bigger
The universe IS space, plus everything that's in it.
same
The Universe is bigger. The Universe encompasses everything we know; it isn't known whether there are other universes.
The Universe
Universe is bigger.