1. is essential as a solvent (as you said) for all the bodies chem reactions. so, you can infere that if the level is not maintained, the ability of these chem reactions to be performed is limited and possibly stopped = v bad
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Is essential for the functioning of the circulatory sytem and removal of wastes etc. If water level is not maintained, dehydration and eventually death
Important to retain certain compounds in solution. Fall in the level of water would change the osimotic-ness of cells and cause substances to move in and out in ways they are not supposed to
hope this was helpful