The component that makes up the bulk of all galaxies is dark matter.
The correct answer is stars. Stars are the main components that make up the bulk of all galaxies. To arrive at this answer, you can rely on scientific observations and studies conducted on galaxies. Researchers have analyzed the luminosity, dynamics, and composition of galaxies to determine the primary constituents. Through these observations, it has been found that stars play a crucial role in shaping the structure and mass of galaxies.
