Sometimes called "Extraterrestrial Biology", isn't so much a power but is a reflection of the character's alien heritage as not home to earth. Heritage as in a character's biological make-up no matter how close a civilization might be to humankind or how closely they look as humans. Individuals with an alien physiology are extraterrestrial in origin and not Atlanteans, Amazons, or other unique physiology.
Although some of the abilities these races have are natural to that of their race they are unnatural to humans and therefore are termed "superhuman" or "super" abilities. Such as many Legion members may look human however their bodies can activate powerful and varied abilities.