There are 13 students with zeroes on the Honors assignment: Global Warming Graph. Here are some instructions and the Table of data you can graph to make-up this missing work.
You will have to create a graph on graph paper, plot the points from the data table, then answer the Challenge Questions. He will need to use slope of the graph to answer #2. I used the slope of the line from 1995-1998. Calculate (367-361) divided by 4 years to get the parts per million per year. Then project that slope for the dates up to 2015, or even to 2020. I think I got a slope of around 2 ppm/yr. So that would mean 22 years for 2020. 22years x 2ppm = 44ppm increase. 44 ppm must be added to the existing 367ppm to get the total concentration.