WORLD HISTORY

Detailed explanation-1: -To date, there’s only one species that has been called ‘biologically immortal ‘: the jellyfish Turritopsis dohrnii. These small, transparent animals hang out in oceans around the world and can turn back time by reverting to an earlier stage of their life cycle.

Detailed explanation-2: -Immortal is the opposite of mortal or death. But immortal beings can often be killed by other immortal beings so long as you burn them, cut off their head, pull out their heart, etc.

Detailed explanation-3: -Biological immortality is an absence of aging. Specifically it is the absence of a sustained increase in rate of mortality as a function of chronological age. A cell or organism that does not experience aging, or ceases to age at some point, is biologically immortal.

Detailed explanation-4: -Markandeya, a sage who was granted immortality at the age of sixteen. Sir Galahad (born 2nd-6th century), one of the three Arthurian knights to find the Holy Grail. Of these questing knights, Galahad is the only one to have achieved immortality by it.

Detailed explanation-5: -Regenerating flatworms This apparently limitless regeneration also applies to aging and damaged tissue, allowing the worms to cheat death indefinitely, according to a study at the University of Nottingham.