“Pure prehuman and micro-organic chemistry,” Aaron broke in.
The micro-organic world was an invisible world, a world we could not see, and we knew very little about it.
You see, the micro-organic world remained a mystery to the end.
microorganism mi·cro·or·gan·ism (mī'krō-ôr'gə-nĭz'əm)
An organism of microscopic or submicroscopic size, especially a bacterium or protozoan.
An organism that can be seen only with the aid of a microscope and that typically consists of only a single cell. Microorganisms include bacteria, protozoans, and certain algae and fungi. See Note at germ.