You Really Were Anus First

Humans are deuterostomes, meaning that the first opening to form in the early embryo is the hole that becomes your anus, not your mouth. In this group, the blastopore, an initial dimple in the developing ball of cells, goes on to form the digestive tract’s exit, while later openings become the rest of the gut. In simple terms, at one point in your development you really were nothing but an asshole in progress.

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