Dear Mr. Wood,
I'm glad that you wrote back. I think that the answer to question #1 is that the graph is showing about 387 parts per million (averagely) and I say this because most of the points graphed were at 387 and those that weren't were at 386 and 388. For the second question, I think that the data was collected at sometime around or in between 8-10 pm because that is when photosynthesis has occurred and the carbon balance would have been lowered. And for question #3, I think that the amount of CO2 will increase because photosynthesis is over and the plants aren't taking in (as much) CO2. Anyway, I hope you're having a good time and learning something new everyday.
Sincerely,
Elizabeth Markus
Period 6