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Did you know that we used to have a tail? There are at least three pieces of evidence in the human body showing that we used to have tail-wagging days.
1) Bone - the coccyx bone is also known as the tailbone. It sits at the very end of the spinal column, in between the butt cheeks. It is can be broken when people fall "flat on their bum". It is the boney remnant of our former tail.
2) Embryology - embryos develop a tail after about a month of development (called the caudal eminence), but it later regresses except for the coccyx.
3) Nervous System - the filum terminale it is the last part of the spinal cord. It was the nerve that supplied our tail, yet we still have it in our bodies today.
P.S. Does baking chocolate chip cookies count as NPLEX prepping? You know, because studying requires snacks!