Answer to Question 1
FALSE
Answer to Question 2
Life and oxygen also explain the presence of Earth's ultraviolet-absorbing stratosphere. In the upper atmosphere, chemical reactions transformed some of the O2 into molecules of O3, ozone. The ozone molecule absorbs solar ultraviolet energy better than O2, creating the warm stratosphere. Since Mars and Venus lack photosynthetic life, they have too little O2 and too little ozone to form a stratosphere.