Scrape a knee and, along the whole edge of the wound, cells begin dividing sideways to close the gap. They stop when they meet in the middle. Nothing supervises this. It is happening on someone, somewhere, every second of every day.
The present tense is where such things are hardest to believe, because none of it is visible from a chair. And yet, while you read this, something in you is under repair that you will never see, never thank, and never need to authorise.