A type of jellyfish has been found to be one of the few organisms on Earth that could be considered immortal. The Turritopsis dohrnii jellyfish has the ability to regenerate its cells back to its first stages of life. It begins life as a polyp, a small cylinder that attaches itself to the sea floor, before it matures into an adult jellyfish and detaches itself. Instead of dying as it reaches the end of its maturity, the Turritopsis dohrnii can regenerate its cells back to the polyp stage and starts its growth cycle all over again. Not all of these jellyfish are immortal, however, because the regeneration process typically occurs only as a result of dangerous situations, such as starvation or other physical damage.
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