Why water does not come out of a dropper unless its rubber head is pressed hard?

Why does a rubber can be compressed ?

Why a fish can not servive out of water?

Water comes out of a cell when it is placed in:

When we press the bulb of a dropper with its nozzle kept in water , air in the dropper seems to escape in the form of bubbles. Once we release the pressure on the bulb , water gets filled in the dropper.The rise of water in the dropper is due to pressure of water gravity of the earth (c) shape of rubber bulb atmospheric pressure.