The transfer of water between the atmosphere, the oceans, and the continents is known as the

 "hydrologic cycle" .

I'm pretty sure it's c. extremely gradual but not 100% sure though.

It is useful for historians to write narratives so that history can be passed on from their point of view.  think about a story being told in third person, then think about it again being told in first person, by someone who actually experienced the event.