unicellular

Such unicellular organisms generally are so small that we’d need a microscope to see them.

Protists and ArchaeaProtists are mostly unicellular, but are more complex than bacteria as they contain a nucleus.

The first living organisms formed their hierarchies thus: individual unicellular, or plastide; group of plastides or meride.

The multicellular organism was a colony of unicellular organisms, and its life was a sum of the lives of its constituent elements.

They appertain to cells not yet differentiated, to the unicellular organisms which occupy the first stages of life.

Weismann deduces from this a radical distinction between the unicellular and the multicellular organisms.

In the most primitive kinds of the unicellular protists we find the phenomena of death and regeneration in the simplest form.