感=Sensation of something could be anything./感觉=Feeling of something. Feels
奔跑(running at a very fast speed /跑=Run（You can tell that someone or something is moving at a faster than walking or normal speed,but you can tell that person or thing is NOT moving at a very fast speed.
口= Referring to an opening space that could let something in or out and it could be anything/嘴巴= it only refers to mouth of animals, nothing else.
面= The surface of something/边=The edge of something
维持= To keep or maintain something in order to keep the same size or amount for a long period time/保存= To save or store something in a specific space, so that you will be able to use that thing in the future.