Hi,
So, this is what the Foundation says:
"All sources appearing in the bibliography must be cited in the resubmission statement or the project description questions. In-text citations should take the form of the authors' name/s followed by the date: (Sahlins 1961) or (Aiello and Wheeler 2003) or (Aiello et al. 2002)."
Therefore, every item that makes its way to your Bibliography needs to be necessarily cited in your answers.
I hope this helps
Good luck for tomorrow!