If you have answered "yes" to these five questions you have probably located a scientific article.
Your professor expects you to use the scientific or peer-reviewed journal literature to support the ideas presented in your seminar. Here's a quick overview of how to identify these journal articles.
If the article is NOT written by the person or group who did the research, it is NOT a peer-reviewed or scientific article. Don't be misled by journal titles like Scientific American or Bioscience. They are great magazines but they don't publish original research.