What does the cosmological principle state about the universe?

Hint: Here we are asked to write the statement of the cosmological principle of the universe. Before solving we need to know the basics that an observer's view of the universe depends neither on the direction in which he or she looks nor on his or her location. Using this statement we can explain the given problem.

Complete answer:
This principle states that the matter distribution in our universe is homogeneous and isotropic on a large scale. This comes from the fact that although the universe is inhomogeneous at smaller scales, it is statistically homogenous on scale transfer than $250$ million light years. Another thing in this principle is that the cosmic microwave background is isotropic, which is to say that its intensity is about the same whatever is the direct that we are looking at. Hence from this we can say that we do not occupy a special location in space because the universe is the same everywhere on an average.

Note: Remember that extension of this principle is called perfect cosmological principle. Big-bang model the second assumption is called the cosmological principle. This principle is important because it allows the universe to change or evolve throughout the time. Note that this principle also implies that our universe is non-static and flat. Keep in mind that our universe appears smooth at large distances.