Yes! You may re-take any of your courses when it's offered in a future session. Each offering of a course is assessed independently and most edX courses do repeat. Please note that payment for one session doesn't apply to a future session: Can I transfer to another session?
However, it's not possible to start fresh or reset your course progress in the same session, so make sure you study and prepare well before taking graded assignments.
Note: Un-enrolling from and re-enrolling in the same course session won't reset your course progress.
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