When is it important to try to determine the credibility of a source? Why is it important?

Because the audience will expect you to back up your assertions with credible evidence. If you don't get it from a credible source the audience will not be convinced that the claim is correct or plausible.

pinterest: xxxsociety (if anyone sees this follow me on there xd)

there were 6 major base camps.   the base camps were located in alva, fort reno, fort sill, the madill provisional internment camp headquarters, mcalester and camp gruber.