Brainliesttt asap! which of the following correctly describes the hierarchy that exists in the universe? a galaxy refers to all existing matter, energy, and space that is held together by gravity. a galaxy is a collection of planets, their moons, and other objects in orbit around a central star. a solar system refers to all existing matter, energy, and space that is held together by gravity. a solar system is a collection of planets, their moons, and other objects in orbit around a central star.