Do Universities look at Final Marks?? (Best Answer!)?

1.I applied to some universities and want to know if the universities can consider an applicant's final mark instead of just looking at the mid term mark. The deadline for responding to a University is on May 28th and my average right now is a B. I know that my average will go up bit. I want to know if the universities can postpone the deadline date so that they can see my final mark. I know that my final mark will be better than my midterm mark. I got accepted into Brock university and the deadline is May 28th but i really want to stay close to home and go to UOIT so i can save money. I still haven't heard from UOIT and I still want to work hard to improve my average a bit. 2. Also if i accept Brock, will the other universities not accept me anymore???. Im so confused. Please help