The Assignments tool in D2L has an integration with TurnItIn.com that allows instructors to check for plagiarism in student assignments. This integration must be turned on by the instructor.
If an assignment has been run through Originality Check, and your instructor chooses to allow students to see the results, you may see an Originality Report next to your assignment while viewing feedback or your assignment history.
Click on the Originality Report to open your assignment in TurnItIn.com and view any passages that have been marked/flagged as unoriginal work.
If you would like to know more about plagiarism and how to avoid it, The University Libraries have created a great resource on Avoiding Plagiarism for your use.