We cite, or refer to, our sources in research assignments for (basically) 4 reasons:
To give credit to (or not take the blame for!) the "author" of the idea or quote
To support and highlight our own idea/argument
To show evidence of all the research we have done
To become part of the academic or scholarly "conversation" about our topic
Watch this quick video about why we cite to get a clear picture of why it's so important to use citations:
What if rappers had to cite all their pop-culture references? How many of these would you recognize without the citations?