If calcium levels within a man’s blood drop too low it can result in twitching, depression, coma, or even death. which characteristic of life is the man being affected by?

living things must maintain homeostasis.
living things are made of cells.
living things require energy.
living things reproduce.

The answer is going to be a because ik that i’m right

Atp is is our little "pocket" of energy. of course, if you have too little, then it means you have too little energy, and you'll pass out. the way to not have enough, is to have no energy sources (glucose, fats, proteins). you can't have too many atp molecules. cycles like the krebs cycle produce it, but if you have too much of any substrate (or too little for that matter), the cycle stops and atp is no longer made (it stops until substrate levels are such that the process can go on). in any case, this is unlikely since atp is constantly hydrolyzed and remade, even while you're asleep. you won't have too much. if you have zero, you are dead or dying.

Your answer is water because there is combined mass of water found on, under, and over the surface of a planet. your answer is water.