i want to know what is scuba diving
As you have known it requires water and the diver utilizes  a self-contained underwater breathing apparatus (scuba) which is completely independent of surface supply, to breathe underwater.
interesting tell me more about it
Like i said their apparatus is completely independent of surface supply, hence they  carry their own source of breathing gas
how do breathing gas look like does last long
Well, they use compressed air, allowing them greater independence and freedom of movement. this makes it better for them that  surface-supplied divers