General Properties of protozoa Protozoa are one-cellled animals with full vital functions They may be freeliving or parasitic Protozoa are minute parasites and can only be visualized under the mIcroscope.▪ General Properties of protozoa ▪ Protozoa are one-celled animals with full vital functions. ▪ They may be freeliving or parasitic. ▪ Protozoa are minute parasites and can only be visualized under the microscope