Black Holes--Kim and Julia

1.) What are the parts of a black hole?
----an object of dying stars
2.) How is gravity related to a black hole?
----gravity is ????
3.) How can we see the holes if they are black?
----because the light trying to escape the center and we see the light
4.) What's a Swarzschild radius?
----(gravitational radius) r_s equal to the mass