 If I told you that a mutation in your DNA of your cell actually could result in a cancer. I wear sunblock, I don't drink alcohol, I don't smoke cigarettes, I should be safe, right? Wrong. And the reason is because those 40 trillion human cells have to divide, which means they have to copy paste each other, right? If I gave you a one page document and asked you to copy it on a laptop 10 times, like a paragraph, you would get it probably 100% correct. If I asked you to copy it 40 trillion times, you definitely will screw up a lot. And that's what happens in the human body. Just the copy-pasting function actually causes mistakes. And do you know in the typical human body, every 24 hour, how many DNA mistakes are made? 10,000 DNA errors are made every 24 hours. Let me come back to the question. How come we don't get cancer more often? Because our DNA, our defenses, fix it.