The thermometer in the [black] paper shows the greatest increase in temperature because black [absorbs] all wavelengths of visible light. The thermometer in the [white] paper shows the smallest increase in temperature because white [reflects] all colors of visible light. The thermometers in the green, red, and blue paper all show an increase in temperature. However, they don't increase as much as the thermometer in the black paper because these colors [absorb all other colors and reflect their own color.]
Oxygen is a diatomic element hence exists as O2 for majority of its existence in our atmosphere. Although small portion does exist in form of O3 which protects earth from sun's harmful ray, the majority portion of oxygen has O2 which is the oxygen we breathe.
