One thing about biology I don't understand at all (not that I've ever really tried to learn about it) is how cells "know" what structure to build where. Can anyone ELI5?

Short answer is no one knows, but there's tantalising evidence that it has to do with macro extracellular electric gradient in tissue: https://www.youtube.com/watch?v=RjD1aLm4Thg

Every cell contains the entire genome which, informed by chemical messages from cells nearby, has a subset of genes activated which encode the information needed to know what to do.

Even the simplest cells on Earth are extremely advanced and intelligent, the latest in 4 billion years of evolution

It's fascinating how the same type of cell is used throughout the body to make different body parts. It's like nature came up with an abstract <Cell /> component that it reuses to compose a body.

> The growth wasn't cancerous, but it was secreting a "thick copious mucus-like material"

So she was actually growing a runny nose on her spine.

I'll bet it was very mucous-like. very.

(and it is actually quite amazing when you think about it)

The thing of nightmares...

> One woman in Los Angeles, for example, spent $20,000 on a wacky cosmetic procedure that took stem cells from her belly and injected them into her face. She later grew an extra bone that prevented her from opening her eye and scratched up her eyeball.