Answer:
Dust, gases, billions of stars, and solar systems
Explanation:
A galaxy is a large group of dust, inter stellar gas, stars, solar systems, stellar remnants, dark matter. Some galaxies have over several billions of stars.
Small galaxies are known as dwarfs, which contain a few hundred million stars while large galaxies are known as giants which contain up to a hundred trillion stars
Therefore, the correct option is dust, gases, billions of stars, and solar systems
