Define the term - Soil protozoa

These are unicellular but larger than bacteria, the size varying from a few microns to a few centimeters. The protozoa exist in all aerable soils, but numerically form only a small part of the soil population. A fertile surface soil may contain 10,000 to more than a million of protozoa per gram of soil. Soil protozoa tolerate adverse environmental conditions such as moisture, acidity, and climate to a greater extent than other soil microbes. The role of protozoa in soil is not definitely known.  As they feed on the bacteria and actinomycetes, they probably help to maintain a favourable balance of the microflora in soil.