Photochemical smog results from automobile pollutants reacting with ultraviolet light from the sun. <span>Nitrogen oxides released from the automobile are introduced into the atmosphere reacts with sunlight to produce singular oxygen atoms. Oxygen atoms then combine with molecular oxygen to produce ozone which is one of the components of photochemical smog.</span>
Violet and blue have the high frequencies (thus energy) of visible light. Red will be the least energy but lowest energy. And remember, chlorophyll is green because it reflects green into our eyes. Green is therefore not absorbed, so not used for photosynthesis.
"Exponential growth" means that the bigger it is, the faster it grows.
That's Choice 'D'.
I don’t know how to explain it but this might help
