You are not a person, you are a planet, made of roughly 40 trillion cells. There is so much of you, that if your cells were human-sized, you would be as big as 20 Mount Everests. For your creepy-crawly inhabitants, this makes your body an ecosystem, rich in resources and warmth and space. A perfect place to move into and have a family. While some of these guests are welcome, most are not. Your immune system is the guardian of this planet, the force tasked with protecting yourself against the constant danger of invasion.

Want to dig deeper into the subject of the immune system? Kurzgesagt has just released its new book, Immune: A Journey into the Mysterious System That Keeps You Alive! A great way to support one of the best Youtube channels out there and feed your brain with important knowledge!

–Immune: A Journey into the Mysterious System That Keeps You Alive (Hardcover)

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