The kind of Cells. Habitat is a place where diverse types of organisms live together. It cannot be used for classifying organisms. Cells have specific structure, prokaryotic in monerans and eukaryotic in the remaining organisms. Organisms are unicellular in protista and multicellular in others. A cell wall is absent in animals. Cell wall contains chitin in fungi and cellulose in plants. Plastids occur in plant cells. They are absent in animal cells.