The bar graph gives the average atmospheric concentration of carbon dioxide. a. Estimate the yearly increase in the average atmospheric concentration of carbon dioxide. Express the answer in parts per million. b. Write a mathematical model that estimates the average atmospheric concentration of carbon dioxide, C, in parts per million, x years after 1950. c. If the trend shown by the data continues, use your mathematical model from part (b) to project the average atmospheric parts per million Average Atmospheric Concentration of Carbon 500- 400- 300- 310 318 328 339 355 370 389 398 200- Dioxide 100- 19501960197019801990200020102015 a. The yearly increase in the average atmospheric concentration of carbon dioxide is approximately ppm per year. (Round to the nearest tenth as needed.)