Which kingdom includes organisms that are unicellular, multicellular, aggregate and colonial in cellular arrangement? A) Archaebacteria B) Eubacteria C) Plantae D) Protista

The one that best fits the description given is the Protista. The protista kingdom comprises of both the unicellular and multicellular organisms. They are considered eukaryotic but cannot be categorized either an animal, a plant or even a fungi. So the answer is option D.