The kingdom _______ is a heterogeneous grouping of unicellular, colonial, and multicellular eukaryotes, including slime molds, brown algae, and diatoms.
The term that best completes the statement is PROTISTA. It is the Kingdom protista that is considered heterogeneous because it both consists of eukaryotes that are unicellular and multicellular but these cannot be classified as either an animal or a plant.