The variation range within each species. Some plants and animals have a greater range than do others. For example, the chrysanthemum has been found to produce a very wide range of variations. In contrast, the cheetah has been found to have one of the narrowest ranges of any mammal. The amazing eye.
Every eye is amazing, no matter which creature it is on.
Yet it would be impossible for one eye to change over to another type. The differences are too great. Each eye would have to come into existence exactly right and all at once. The cell battery. ATP is the chemical compound in cells which provides them with energy.