Why do black holes have a massive force of gravity? a
They have small masses and small diameters
b
They have large masses and small diameters
c
They have large masses and large diameters
d
They have small masses and large diameters

A black hole is a region of spacetime where gravity is so strong that nothing no particles or even electromagnetic radiation such as light can escape from it.  Black holes are caused because of a supernova. A supernova is an exploding star that blasts part of the star into space.

The gravity is so strong because matter has been squeezed into a tiny space. That means, the large mass centers into the small diameter so Large mass comes in the small diameter which makes the strong gravity.

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

increased stability in the completion of fluorine's outer shell.