Hi Mr. Wood. How have you been. Sorry didn't do this till the last day, but it is done now. Here are my answers......
The CO2 in the graph is between 386-388 parts per million
The data was collected in the late afternoon or evening.
In 2 or more hours, there would be less carbon dioxide at night because the plants are not using the carbon dioxide for photosynthesis. There also isn't any sunlight yet.
-THANK YOU SO MUCH!! Rebecca Hogan