“Look inside this incubator. These eggs were laid 21 days ago and this one is just about to hatch. If you listen you can hear the chick pecking at the inside of its shell. Soon it will break through and take its first breath of fresh air. It’s a dramatic moment, that first breath, one shared by so many creatures, including us.
But hold on. Think about this: When you were in the womb, you got oxygen from your mother through your umbilical cord. But for the last 21 days, this chick has been cut off from its mother, sealed inside an egg. So how does it get oxygen?”
“A chick embryo, sealed inside its egg, must find a way to get oxygen without its mom — and long before it has working lungs.”
Follow this with The Cycle: Carbon and Oxygen and You, oxygen’s surprisingly complex journey through your body, and more animated explainers from Skunk Bear on this site.