EVIDENCE
When you're writing about a topic and trying to prove a point, you need EVIDENCE to back up your opinion.
Your evidence needs to come from a source that is reliable. Evidence can be written facts, sets of numbers, graphs, or pictures - anything from your reliable source that proves your opinion is correct.
Whatever you use for evidence, you need to either directly quote it or you need to paraphrase it in your writing to prove to your readers that what you are saying is true.
Every time you include evidence in your writing, be sure to include a citation and explain your evidence clearly and completely.