it's not all literal. just the general idea. as for Earth being 6000 years old, i don't think it says that anywhere. God created man as he created everything else. and created woman under the same human form with different body parts.

same thing goes for the monsters in the form of many different beasts. they aren't literally mutant creatures, instead they are forms of nations or people.

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"And those who resisted were dragged out from their homes. This necklace was fashioned out of their teeth and bones."