Question

What species of jellyfish are deemed biologically immortal?

Answer 1

Biological immortal:

1. Biological immortality is a state in which the rate of mortality from senescence is stable or decreasing, thus decoupling it from chronological age.
2. Various unicellular and multicellular species, including some vertebrates, achieve this state either throughout their existence or after living long enough.
3. A biologically immortal living being can still die from means other than senescence, such as through injury, poison, disease, lack of available resources, or changes to environment.
4. Unicellular organisms are considered biologically immortal.

Turritopsis dohrnii,

1. Turritopsis dohrnii, is the only "immortal jellyfish," species that can hit the reset button and come back into an earlier developmental stage.
2. In case of injury or threat-like condition, Turritopsis dohrnii take up a larval stage, called a planula, which develops from a fertilized egg.