A galaxy. They vary in size, of course.
galaxy are group of billions of stars
Yes. A group of stars called a galaxy. One of billions in the Universe. An awesome thing it is too. Truly awesome.
When billion of stars are in a concentrated dense cloud it is called a galaxy.
That is a galaxy. The one we live in is called the Milky Way. There are millions of other galaxies in the universe, many of which have a spiral structure (and probably a black hole in the middle).
The verb in the sentence is "is," which is a form of the verb "to be."
Billions of stars make up galaxies. Galaxies are vast systems of stars, planets, gas, and dust that are held together by gravity. Our Milky Way galaxy, for example, consists of billions of stars including our Sun.
You can't list "all the stars" in a constellation; there are billions upon billions of them.
A galaxy contains billions of stars. A universe contains billions of galaxies.
Because they are billions and billions and billions of miles away from us.
The universe.
The Perseus Arm of the Milky Way galaxy contains the Sun.
the trillions comes after the billions!