No. All the stars you see at night are in our galaxy. Stars in other galaxies are much too far away to be seen without a powerful telescope.
Yes all binary stars are part of the star system because all galaxies and universes have stars and you have to have at least two stars for it to be binary stars.
You can also distinguish them by the types of stars - older stars versus younger stars, and stars of different "metallicity".
All stars and galaxies are in the universe.
No stars are actually a galaxy. All stars are stars and all galaxies are galaxies. Stars are found in galaxies. Some galaxies look like tiny dots in our night sky, so might look like a star, but they are not stars; they are galaxies.
the universe is made up of galaxies
The collection of all visible or detectable galaxies is known as the universe. Each galaxy is a vast collection of stars--billions of them. Some galaxies have trillions of stars.
It is impossible to list them all. There are 100 billion galaxies in the known universe, each containing millions to trillions of stars.
Both - all galaxies contain young and old stars.
All of them
No, there are more massive galaxies with stars in them.
All galaxies are massive clusters of stars scattered across the universe. Many galaxies take the same form, for instance, spiral and elliptical galaxies. Some galaxies also have a black hole in their center.
A cluster is a collection of galaxies, normally less than about 50 galaxies. All clusters are different and all galaxies are different. A ball point figure would put the maximum number of stars at around 10,000,000,000,000 stars or 10 trillion.
Galaxies are vast collections of stars. So I guess you could say that a big group of stars forms a galaxy. Our galaxy has many big clusters of stars within it, so not all star clusters are galaxies. If you have a cluster of several million or billion (or trillion) stars surrounded by a lot of empty space, that is probably a galaxy.