What part of a divers body is most effected by pressure?

The lungs are most affected by the pressure.
It makes breathing difficult pressure get higher and it compresses the diver's lungs.

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water