Hmm immortality. I feel the jelly fish doesn't have real immortality, since it just reverses time when it gets old. It's just cheating death😝
I recently came across a type of shark(can't remember the name. It's quite ugly though) that has been living for at least 270 years, and possibly 500 years. So this shark was alive in the 16th century😮.
But it still isn't immortal, as it also ages, albeit very slowly. Nice article, very well researched.
RE: HUMAN AGING, AN UNDYING FISH AND THE CONCEPT OF TRANSDIFFERENTIATION