Answer:
When I am writing a research paper, or answering questions, I typically find a reliable source and use facts to prove how the said subject is relevant.
Example: I had a paper over how William Shakespeare was relevant/influenced the modern marketing/business world. My claims as to why he was relevant were that he is one of the most well known names in history, and he has built a brand around his name (his playwrights) that can be associated with him. I used a quite from an article where someone had said that Shakespeare has built himself as the biggest brand, whether it was he who built it.