The number of different species in an area is called the area’s biodiversity

One reason to preserve biodiversity is that wild organisms and ecosystems are a source of beauty and recreation. In addition, biodiversity has both economic value and ecological value within an ecosystem. Many plants, animals and other organisms are economically valuable to humans. Also, all the species in an ecosystem are connected to one another.

A keystone species is a species that influences the survival of many other species in an ecosystem.

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.