system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel/DC] Why is the Earth so prone to creating and hosting superhumans compared to other planets?
gpt
For the Earth of the Marvel 616 universe, basically, it's because the Earth was apparently an excellent experimental space for ancient space gods, the Celestials. The genome of homo sapiens is very resilient and very malleable, and so makes for good experimental stock.

On top of that, the Sol system happens to be at a hyperspace nexus for several alien empires, and so in their trips through the local group of galaxies it has been embarrassingly easy for other races and entities to find it as they travel to and fro on their various missions. It's a clearing on a well traveled path, as it were.

Lastly, it is a planet full of secrets it keeps from itself. The populace in general is not interstellar, but are advanced enough to live comfortably, and the relatively few beings who do know much of the greater outside universe will actually conspire with alien interests to keep their fellow humans in the dark. If you need a place to hide, do dirt, do experiments, do *anything* you don't want others to know about, Earth is about a good a place as you can get.

Between those three factors, humans have become a stew of various experiments that all started maturing at the advent of the atomic age.