system
Given the following post, respond as if you're commenting on Reddit:
human
Why are graves dug 6' deep?
gpt
it is the approximate depth that prevents wildlife from digging it up. both as a matter of moving 6 feet of earth and because the gasses from the body will not filter up quickly enough to be detected by scavengers.

it's also the approximate height of a human being. a digger could easily assess his depth and also get out of the hole under his own power were it necessary.