MONAD, n. The ultimate, indivisible unit of matter (see Molecule). The monad has body without bulk, and mind without manifestation - containing all the powers and possibilities needful to his evolution into a German philosopher . .
When you look more generally at life on Earth, you find that it is all the same kind of life. There are not many different kinds; there's only one kind. It uses about fifty fundamental biological building blocks, organic molecules.
Molecule, n.: The ultimate, indivisible unit of matter. It is distinguished from the corpuscle, also the ultimate, indivisible unit of matter, by a closer resemblance to the atom, also the ultimate, indivisible unit of matter ... The ion differs from the molecule, the corpuscle and the atom in that it is an ion.