In some freshwater organisms there is a structure called a contractile vacuole that regulates water movement into and out of the cell. what explains the existence of the cv?

The contractile vacuole is an structure that helps in regulation of osmotic pressure within the single celled species such as amoeba, paramecium and some algae. The solute concentration in the cytoplasm of these species contains large amount of solute as compared to their surroundings. In order to maintain the solute concentration, excessive water is stored in CV and then expelled out though an opening in the cell

idk

explanation:

i believe you meant to say air rather than hair so the answer is below ")

the dead sea, the lowest place on earth at 430 metres (1,410 ft) below sea level, has a correspondingly high typical atmospheric pressure of 1065 hpa.