Which of the following describes a difference between galaxies and solar systems?
Galaxies contain only moons, while solar systems contain planets.
Gravity holds solar systems in orbits but does not exist between stars in galaxies.
A galaxy is a collection of millions of stars, while a solar system is a star and the planets around it.
It's easier to use astronomical units to measure distances in the galaxy but use light years for measurements in a solar system.

BRAINLIST AND THX IF CORRECT