Nerves send signals to your brain from your spinal cord. If something is burning your nerves will send a pain signal from the area of the burn to your brain through you spinal cord. Then your brain sends a signal back to the nerves that there is pain and you should avoid it. Same with internal nerves and same with touch.
I believe its the first one because manganese is mn and IV is 4 but the cross thing thing will making it the second one but then you have to simplify making it the first one i hope that helps:)
