The correct answer is A. undying.
A hydra is a small, freshwater animal that belongs to the phylum Cnidaria. It is a polyp, which means that it has a cylindrical body with a mouth at one end and tentacles at the other. Hydras are found in ponds, lakes, and streams all over the world.
Hydras are biologically believed to be immortal because they can regenerate any part of their body that is lost. If a hydra is cut in half, each half will grow into a new individual. Hydras can also regenerate their tentacles, their
digestive system, and even their brains.The other options are incorrect because they do not accurately describe hydras. B. perishable means that something can be destroyed or spoiled. C. ancient means that something is very old. D. eternal means that something lasts forever. Hydras are not perishable, ancient, or eternal. They are biologically believed to be immortal.