• Presence
  • Although the ocular pigments of many invertebrate groups have been poorly investigated, there is strong evidence that the dual melanosome morphology and presence of an RPE is a uniquely vertebrate trait. (wikipedia.org)
  • appearance
  • Most cells of the body are differentiated, so that the appearance under a microscope shows that it's a liver cell, part of the kidney filtering mechanism, heart muscle, etc. (cancergrace.org)