As they flow over rotten logs as a fluid sheet, slime molds appear to lack any partitioning into cell units; however, slime molds do become cellular when they change form to produce spores. Also, the surface tissue of some parasitic flatworms are a "syncytium" or layer of living material that contains many nuclei and cell organelles but lacks partitioning by cell membranes. These tissues consume food and produce wastes. Should the tissues of the slime molds or the flatworms described above be considered part of living organisms?