Dear Mr. Wood,
Sorry I'm waiting until the last minute to do this assignment, I have had TONS of homework all week and I just now have time to do it. :-( Anyway, here are the answers that I got :
about 386-388 ppm
about 2:00-3:00 p.m.
I think that the carbon will decrease in two or more hours because the plants will have already gotten the carbon that they need for that day.
Your Student from 6th Period, Emily M.