They don't breathe normally on their own.
They have to use pressure regulators to breathe naturally, overcoming the extreme pressure deep underwater.
A snorkel and oxygen tank help the divers breathe when they are underwater.
Scuba - self contained underwater breathing apparatus
SCUBA stands for "Self-Contained Underwater Breathing Apparatus," referring to the equipment that allows divers to breathe underwater. The term encompasses both the gear used for diving and the activity itself. Mnemonics related to SCUBA often help divers remember essential safety protocols or procedures, enhancing their training and preparedness for underwater exploration.
Self Contained Underwater Breathing Apparatus
So that they may breath underwater.
Pearl divers traditionally used a technique called free diving, where they hold their breath while diving underwater to collect pearls. They typically trained to increase their lung capacity and learn to remain underwater for extended periods. Some divers also used weighted belts to help them dive deeper and return to the surface quickly. In modern times, divers may use scuba gear to breathe underwater more easily and safely.
scuba
Scuba Bob's Ocean Quest - 2006 Underwater Heroes Steel Divers 2-6 was released on: USA: 2007
You can breathe underground by using submersible breathing aparatus similar to scuba gear used by divers.
By oxygen tanks - similar to SCUBA divers.
A SCUBA (self-contained underwater breathing apparatus) tank
Diving bells work by trapping air inside a chamber, allowing divers to breathe and maintain pressure as they descend underwater. This air supply enables divers to explore the underwater world safely by providing a controlled environment for them to breathe and communicate while underwater.
they need to know how long they can be underwater, and how deep they can go with the air in the tank.