Homeostasis

Too much water: cells burst + we die of water intoxification

Too little water: cells shrivel + die. We die because we can't carry out functions

Too little salt: heart conductivity suffers, potential death by heart attack

Too hot: enzymes denature, processes can't work, we die

Too cold: enzymes slow, reactions too slow, we die of frostbite, hypothermia, or just death

Too hot: protien coagulates (basically cooks) so our muscles won't work anymore. we die because a cooked heart= not good.