You must acknowledge the source of any information included in your assignment.
You need to cite when you use someone else's exact words (quotation) and when you use some else's ideas (paraphrase).
Your instructor needs to know which parts of your assignment are your original thoughts and ideas, and which parts of your assignment are someone else's ideas. It is a good idea to use someone else's thoughts to support your assignment, but you must give credit to that person. In school, we give credit using citation.
Want to learn more about citation? Check out our Citation Guides.
Remember: you need to credit your source using citation when you use any ideas from other people!

Graphic by Sara LeBlanc, University of Waterloo. Text adapted from University of Waterloo Library (CC-BY-NC).