Who knows the neutrons, the protons, the exact number of molecules in that object or part of that animal exactly that moment. So that mass, for example at the zoo, it might take on a value anywhere between, well maybe close to zero. Close to zero. There's no animal that has zero mass. But it could be close to zero if we're thinking about an ant or we're thinking about a dust mite or maybe if you consider even a bacterium an animal. I believe bacterium is a singular of bacteria. And it could go all the way, maybe the most massive animal in the zoo is the elephant of some kind.