Free divers do but scuba divers do not need to. Scuba divers take their air with them and would have no need to hyperventilate.
they need protection from stuff
They need to know how to swim away from sharks and such!
Hell if ik..
Like all adults or older teenagers; scuba divers need English and Maths also physics and scuba diving training. Hope I answered your question xx
they need to know how long they can be underwater, and how deep they can go with the air in the tank.
It pervents the water pressure from killing the diver
PASSPORT
Generally no. They need to be quite fit to be able to swim in the water :)
A bubble of divers
no, don't need it.
Because lungs are not adapted to absorb oxygen from the water.