19. Which of the following does NOT cause chemical changes in the composition of rocks A. abrasion B. dissolution C.hydrolysis D. oxidation 20. How the conduction in the surface of the earth affect the temperature of our atmosphere A. Air molecules do not come in contact with the warmer surface of the land and ocean resulting to the increase of its thermal energy. B. Air molecules do not come in contact with the cooler surface of the land and ocean resulting to the increase of its thermal energy C. Air molecules come in contact with the warmer surface of the land and ocean resulting to the increase of its thermal energy​