You will need to follow MLA standards for your science project research paper (if you chose that option) and part of your PowerPoint presentation (if you chose that option).
If you're writing the paper, there's a clear and concise summary of the general format for an MLA paper that you should follow here.
If you're doing the paper or the PowerPoint presentation, you'll need to do a works cited page. You can find instructions on how to do that here for the basic format and here, here, here, and here for more specific sources. .
Remember, if you have any questions, ask your biology teacher!