Organs are made by:
Unicellular or multicellular organisms composed by millions of eukaryotic cells among which are yeasts, molds and mushroom-producing organisms.
Animals or organisms composed of a single eukaryotic cell (with a defined nucleus), found in aqueous media, can be solitary or live in colonies. Ex: Euglena sp. and Paramecium sp.
Organisms composed by a lot of cells (millions) with particular characteristics like: Cell wall (composed by cellulose) Chloroplasts Chlorophyll
Systems are composed by:
Animals or organisms composed by a lot of eukaryotic cells (millions), they are heterotrophic.
The tissues are composed by:
Organs
Plants
Tissues
Fungi
Eukaryotic cells
Protista
Animals