Creationism in school?

What do you say when a student believes in creationism?  That the reason that we have life on Earth is not because of the sun and the relationship to the Earth or that there is oxygen on our planet, or water to live?  It is because God created it.  I just experienced this one in my social studies class of all places.  Students were discussing how and why we have life on the Earth and how the climates affect the different regions. I was looking for answers that the Earth is heated by the sun gives us light to change into energy but when a student answers that it is God's doing...what are you suppose to say?  I simply stated that according to the text book the reasons were the ones we were discussing and be sure to answer that way for the tests.  But was that the right thing to do?