Not cooperating with one's group may lose you points and will anger me greatly enough that I won't do you any favors. An excellent paper-characterized by insight, originality, substance, and stylistic maturity. C A satisfactory paper-adequate and average in both content and expression or good in one but poor in the other. D A poor paper-below average in either or both content and expression without compensating strength in the other. F A failing paper-either completely failing to address the assignment or containing serious and repeated writing errors that markedly interfere with its reading or combining general emptiness of content with overall weakness of expression.
American conventions require a comma with a coordinating conjunction joining two sentences.
You will just have to make more adjustments than speakers whose dialects are close to the written language. Note, though, that I do not type all the handouts you will receive. Don't be wishy-washy in your writing. Do, however, differentiate between what you're presenting as simple facts, as conclusions, and as mere speculation. It may be an inelegant thing to do, but a preposition is a perfectly grammatical thing to end a sentence with.