Answer:
Some of the key characteristics of galaxies and galaxy clusters include their size, shape, and structure. Galaxies and galaxy clusters are also distinguished by the presence of dark matter, a mysterious substance that is thought to make up most of the mass in the universe. Additionally, galaxies and galaxy clusters are important sites for the formation and evolution of stars and other celestial objects.
Step-by-step explanation:
Galaxies are vast collections of stars, gas, and dust that are held together by gravity. They come in a variety of shapes and sizes, ranging from small, irregular galaxies to large spiral galaxies with well-defined arms. Galaxies also contain a central region known as the nucleus, which may be home to a supermassive black hole.
Galaxy clusters are groups of galaxies that are held together by gravity. They are the largest structures in the universe, and they can contain hundreds or even thousands of individual galaxies. Galaxy clusters are typically separated by vast distances, and they are bound together by the mutual gravitational attraction of their constituent galaxies.