Paramecia are unicellular. They are microorganisms that are classified under the protoctist phylum Ciliophora. They are cilliates that are characterized by long cilia that continuously beat to help the microorganisms move.
Paramecia perform all of the same functions as multicellular organisms, but they do not have structured organelles or any specialized cells. They use an elaborate ultrastructure to carry out the same functions as multicellular organisms. Paramecia contain one macronucleus and one or more micronuclei that allow them to grow, reproduce, develop and maintain homeostasis. Their nuclear dualism allows them to pass on unique genetic characteristics to their offspring and maintain their physical and internal structures.