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Since humans have evolved little since prehistoric times, you have to look at prehistoric society to determine why this is true. It’s pretty simple, actually. First of all, they didn’t have guns back then ;/ But more importantly, if a guy was physically fit back then, others were less likely to pick a fight with him, and he was more likely to win even if they did. Also, being physically fit meant he would be faster and better at gathering food for the family.</p>