No one knows the answer to that because astronomers haven't been able to explore any other galaxies besides the Milky Way.
ALL of them, except the Milky Way and the Andromeda galaxies.
no.
they all are in space?
The Milky Way and 16 other galaxies compose the local group.
All galaxies have black holes, even the Milky Way.
Main sequence stars are found in all galaxies.
All of them. The Solar System is part of the Milky Way Galaxy, one of several billion galaxies in the Universe.
Neither. Among those galaxies observed so far, there are many larger than the Milky Way,and many others that are smaller. Enough have been observed to estimate that there arebillions more, of all sizes. There's nothing unusual or unique about the Milky Way, exceptthat it contains us.
The stars in the Milky Way move in the opposite direction of the sun.
The largest Galaxy ever discovered was IC1101, an Elliptical Galaxy, but the most common large ones are Spirals such as the biggest Galaxies in the Local Group, Andromeda, Milky Way, and Triangulum; all Spirals.
-- The Milky Way is one of several billion galaxies in the universe. -- The term 'universe' means "Everything ... all things, all space, and all time". -- Considering either of these factoids, it becomes apparent that the universe is larger than the Milky Way.
Yes. Every star that is visible to the naked eye is in the Milky Way galaxy. You need astonishingly powerful telescopes to distinguish even the largest and brightest stars in nearby galaxies.