What is the difference between electrical potential and electricity?

I was talking to my friend about neurons in the brain and the topic of electricity came up. Apparently brains do not use electricity but electrical potential (with the possible exeptions of frogs) but I cannot find infomation on this in my textbooks, perhaps they are simplified? could someone please explain this concept. Sorry for my poor english.

How much harder is engineering math compared to electrician?

I like math and it's a strong point for me with becoming an electrician. I took the tech courses to and understand trigonometry and precalculus. Do you think it would be possible for me to do engineering math to get a degree. I'm not a kid, and I have young children.

What kind of Electrical Outlet Adapter will I need to go to China?

I am planning to go on a trip to China and I know that China uses a different type of electrical outlet, What kind of converter or adapter will I need to make my US electronics work with it? I will most likely be spending my time at a relatives house, so I wont be able to receive stuff from hotels or anything.