Look, you kind of have to tnr off your brain when it omes to superhero comics. There's planety of stuff to analize but you need to be going in with suspension of disbeleif.

A lot of crap is grandfathered in from the 50s and 60s, too, so a lot of this is just trying to make sense of stuff that was written back before certain things were common knowledge.

...Though some stuff from back then actually makes more sense now than it did back then. Mutants being the "next step" in human evolution simply becuase they were born with super powers barely made sense by a 60s understanding of evolutionary science.

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However, over the years more things about how mutants work have been explained.

1: Mutant powers come from a specific gene-complex that has a number of variations. This gene complex is present in all humans but only activates in some of them, and was planted in the human Genome by the Celestials at the same time they engineered the Eternals and Deviants.

2: This complex has a number of effects other than merely mutant super powers: Mutants are physically tougher, stronger, and heartier than baseline humans to a small but noticeable degree, they are immune to certain viral and bacterial infections, they process drugs and alcohol faster and more efficiently to a noticeable degree, and their bodies decay at a differant rate than human tissue.

3: All modern mutants share a common ancestor in Tuk, a pre-Terrigen Inhuman, that is to say, an engineered hybrid of eternal, neanderthal, and kree.

4: The Deviants exist to absorb and metabolize the "necrofluid" or Celestial that got sick and died on Earth and then interbreed with other complex life in order to pass on a purified form of the resulting mutant potential and the ability to develop superpowers: The genetic factors that allows peope like th eHulk or Spider-Man to get powers instead of cancer from radiation comes from Deviant ancestry.

5: All modern humans have deviant ancestry. Superhumans have noticeably more... And Mutants have a noticeably high concentration of deviant genes, to the point that they could arguably be considered a particularly table form of Deviant. It is implied to be this high concentration of Deviant DNA that results in the X-Gene being able to activate and the shear varity of powers and mutations present in mutants.

Thus: Modern mutants, Homo s sapiens, are literally a hybrid of almost all known human species: Homo s sapiens, Homo descendus, and Inhomo supremis—and through Inhomo supremis, Homo s neaderthalus and Homo imortalus.

So an argument can be made that modern mutants are the next step in human evolution simply becuase they are the culmination of all human life up tot his point.

The only human species on earth who aren't mutant ancestors are Modern Inhumans(who have engineered the crap out themselves since Tuk's lineage branched off) and Homo mermanus who are themselves an of shoot of mutants and are known to interbreed with baseline humans and other mutants so...