Enabling late submissions of timed quizzes?

Is there a way to give a timed quiz with a file upload question that permits late uploads?  Many students taking a 30 minute quiz seem to be having difficulty trying to upload a file at the last...

Practice quizzes with immediate feedback after each question?

Is it possible to structure multiple choice questions that students can answer and then immediately get feedback on their answer for that question (i.e., see if it is correct or incorrect and get an ...