37) All of the following contribute to nitrogen-fixation except a) lightning b) bacteria on the roots of legumes c) the combustion process in car engines d) the Haber process e) the Ostwald process 38) All of the following are true about ozone except: a) It causes skin cancer. b) It is formed in the pollution from car exhaust. c) It can be used to purify water. d) It exists naturally in the upper atmosphere. e) It prevents UV light from reaching the earth. 39) The smallest ionization energies are found in the a) upper left b) upper right c) lower left d) lower right e) impossible to tell region of the periodic table