No, mana. You use mana for magic, but you use it for other things too. [ like, super-fast sword strikes, floating signs outside an inn, etc etc ] They're not the same.
Sure, three. But now I don't know what else to say. There's water? Air? People? Or do those things go without saying? I don't know what's "normal" and what'd interest you, or what you're looking for. If your world's full of magical dinosaurs driving steam engines, at least we're getting somewhere.