Which of the following is the name for a group of stars and their systems that are held together by gravity?

The name for a group of stars and their systems that are held together by gravity is a "galaxy." Galaxies come in various forms and sizes, containing not just stars but also gas, dust, and dark matter, all bound together by gravitational attraction. They can span millions of light-years and contain billions of stars. The Milky Way, which is the galaxy that contains our solar system, is a barred spiral galaxy. Other types include elliptical galaxies and irregular galaxies. Galaxies are fundamental units of the universe and can be observed in clusters, where groups of galaxies are held together by their own gravity, further influencing their behavior and evolution.