Deep sea divers have been using the compressed air containing `N_2` in addition to `O_2` for breathing. When the sea divers breathes in compressed air at a depth, more `N_2` dissolves in the blood and other body fluids than would dissolved at the surface because the pressure at the depth is far greater than surface atmospherice p ressure. when the diver comes towards the surface, the pressure decreases and `N_2` comes out of the body quickly forming bubbles in the stream which restrict blood flow and affect the transmission of nerve impuses. this results into a condition called 'the bends' which is dangerous and painful. To avoid this condition, professionals now use air diluted with helium. As a student of chemistry, can you analyse as to why helium is used?