Suppose your friend is traveling. she calls you to tell you that she has found an animal that is different from anything that she’s ever seen and wants to know if you can tell her what it is. she says that the animal is about the size of her pet cat, but that it lays eggs into a pouch. the babies do not get milk from a nipple, but lap it from pores. what kind of animal has she found?

We can plant more trees and plants.

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.