Final answer:
Dark matter is present in both individual galaxies and clusters of galaxies. Astronomers use measurements of the gravitational effects of dark matter to determine its location and amount in galaxies. Dark matter is thought to make up most of the matter in the universe and plays a central role in galaxy evolution.
Step-by-step explanation:
Current evidence indicates that dark matter is present in both individual galaxies and clusters of galaxies. Astronomers use measurements of the gravitational effects of dark matter on visible objects to determine its location and amount in galaxies. Additionally, the way galaxies move within clusters suggests that dark matter is distributed among the galaxies in clusters. Dark matter is thought to make up most of the matter in the universe and plays a central role in galaxy evolution.