#grain  a small hard particle; "a grain of sand"
  supertype:  #mote__atom__molecule__particle__speck  (nontechnical usage) a tiny piece of anything
  subtype:  #granule  a tiny grain
     subtype:  #microsome  a tiny granule in the cytoplasm
     subtype:  #chondrule  small granule (of e.g. chrysolite) found in some meteoric rocks
     subtype:  #plastid  any of various small particles in the cytoplasm of the cells of plants and some animals containing pigments or starch or oil or protein
        subtype:  #chromoplast  plastid containing pigments other than chlorophyll usually yellow or orange carotenoids
        subtype:  #chloroplast  plastid containing chlorophyll and other pigments; in plants that carry out photosynthesis

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