Revise GCSE Physics

Question:What are the main physical properties of a black hole?

Large mass, small volume and high density

Strong gravitational attraction due to the large mass.

The gravity of a Black hole is so strong that not even light can escape.

There must be a very dense object at the centre of a Stellar Black-hole such as a large neutron star. Otherwise where would the gravity come from? They are not just big holes in space!