I type a lot. Can that cause carpal tunnel syndrome?

Yes. Any activity where the wrist is moving up and down or if it is held in a bent position for a long time can put added pressure on the median nerve and thereby cause symptoms of tingling, numbnes, and pain i.E carpal tunnel symptoms. But if you are typing alot you need to be aware of many things besides just wrist position or you risk other rsi related problems. Good luck.
Unlikely. There are no scientific studies that typing causes carpal tunnel syndrome. There was a study done in sweden that showed that subjects that typed for 8 hours a day had a lower incidence of carpal tunnel syndrome than a matched group that did not type.