Thread:Polandball & Mapping Slovenia/@comment-27681730-20170118191137/@comment-27381593-20170119143100

Well I supposed you would know about them since it's relevant to the topic, but ok.

Specifically, the placenta is the place where the oxygen goes into the fetus, as it's "dissolved" in the mother's blood. Then the oxygen travels through the umbilical cord to the fetus, providing oxygen to the fetus, rendering breathing unnecrssary and substituting for breathing since there's no oxygen to breathe in.