unicellular

yksisoluinen puhekieltä Describing any microorganism that has a single cell
A single-celled organism; a unicell.
1931, Ezra Bowen, An hypothesis of population growth‎

Among unicellulars, the rate of increase is beyond belief.

In unicellulars the uncoupling of the various nutritional and energy sources is much more widely spread.

More or less distinct specialisation of reproductive elements in some unicellulars.