A possible explanation in cellular terms of the physiological ageing of the planarian.
D000375:Aging; D000818:Animals; D002452:Cell Count; D002454:Cell Differentiation; D012038:Regeneration; D012098:Reproduction; D013045:Species Specificity; D014419:Turbellaria / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology