Answer:
Animalcule is an ancient term for all unicellular organisms, whether prokaryotes —such as bacteria—or eukaryotes, such as amoebas.
Explanation:
Animalcule was the name of what we know today as microorganisms, a term used by van Leeuwenhoek in his observations under the microscope.
Single-cell organisms are those that —unlike multicellular organisms— do not need to join together to form tissues, but are simple organisms that can fulfill their functions independently. Single-cell organisms include:
The term animalcule previously included all these unicellular organisms, which have now been defined and classified, being called microorganisms or single-cell organisms.
