In the 18th century, carl linnaeus published a system for classifying living things, which has been developed into the modern classification system. recently the classification system of life was changed to include not five but six kingdoms, as well as three domains. earlier classification attempts were based mostly on structural features. classification of many species, old and new, continues to be hotly disputed as scientists find new information or interpret facts in new ways. now, dna technology has allowed scientists to re-examine the relationships between organisms to refine the classification system. the graphic shows a a six-kingdom model published by thomas cavalier-smith in 1998, which has since been revised to a seven kingdom system. some of the changes made by cavalier-smith were due to advances in the electron microscope that allowed for the discovery that some chloroplasts were found in the endoplasmic reticulum rather than the cytoplasm. each statement suggests a way the 6-kingdom system by cavalier-smith differs from the kingdom system, except: a) cavalier-smith's model adds the kingdom chromista. b) cavalier-smith's model no longer separates prokaryotes and eukaryotes. c) cavalier-smith's model combines archaebacteria and eubacteria into one kingdom, bacteria. d) cavalier-smith's model reorganizes eukaryotes into five kingdoms instead of the 4 commonly accepted.