Please, when asking questions like this, give a little more detail and (although elementary of a request) please write in proper English so we don't misinterpret your question.
Like the name suggests, is when hosts communicate with each other when utilizing a network. Think of web chatting or IMing.
Like the name suggests again, is when the two communicate directly to each other. Like in the case of visiting a webpage or online shopping.
If you're asking about having a client/server relationship on a peer-to-peer network, that's beyond my basic (and I mean basic) knowledge.
Like rubberman said, we don't do homework on this site. Make the effort to do some research and then bring it here when you need something clarified. It honestly looks like that question of yours was just copied from a handout. O.o