black silhouette of microscopic unicellular organisms: protozoa paramecium caudatum, amoeba proteus,

algae amoeba bacillus background bacteria bacterial bacterium biology black caudatum cell celled chaos chlamydomonas chlorella diffluens education euglena eukaryotic glass illustration isolated magnifying micro microbe microbiology microorganism microscopic optical organism paramecium prokaryotic proteus protist protista protistm protozoa protozoan science set silhouette single study unicellular vector viridis white zoology