You have to make a choice about which of two colleges to attend. you can't really explain it, but you feel strongly that you want to choose one over the other. what part of your brain is at work?

Based on the given situation above, when there is this strong feeling that you want to choose one over the other, which is, for example choosing which colleges to attend, the part of the brain that is at work is the emotional brain. 

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.