In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organs, organisms, andecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, frombacteria to humans.[1][2] Regeneration can either be complete[3] were the new tissue is the same as the lost tissue,[3] or incomplete[4]were after the necrotic tissue comes fibrosis.[4] At its most elementary level, regeneration is mediated by the molecular processes of DNA synthesis.[5][6] Regeneration in biology, however, mainly refers to the morphogenic processes that characterize the phenotypic plasticityof traits allowing multi-cellular organisms to repair and maintain the integrity of their physiological and morphological states. Above the genetic level, regeneration is fundamentally regulated by asexual cellular processes.[7] Regeneration is different from reproduction. For example, hydra perform regeneration but reproduce by the method of budding.