Final answer:
The statement is false; clusters of galaxies have higher mass-to-light ratios than individual galaxies, indicating the presence of a substantial amount of dark matter within the clusters.
Step-by-step explanation:
The statement that individual galaxies generally have higher mass-to-light ratios than clusters of galaxies is false. In fact, individual galaxies, including their outer regions, usually have mass-to-light ratios as high as 100. This high mass-to-light ratio indicates the presence of a significant amount of dark matter. On the other hand, clusters of galaxies have even larger mass-to-light ratios, reflecting that dark matter is present not just within individual galaxies but also in the space between galaxies in a cluster.
For instance, the luminous parts of galaxies with active star formation typically have mass-to-light ratios in the range of 1 to 10, while galaxies consisting mostly of older stellar populations, such as ellipticals, have mass-to-light ratios of 10 to 20. However, when considering entire clusters of galaxies, the mass-to-light ratio can be well over 100, as the total amount of dark matter in clusters exceeds more than ten times the luminous mass contained within the galaxies themselves. This indicates that dark matter contributes significantly to the overall mass of galaxy clusters.