Because in the dark only the rods are the working part in your eyes and they only detect dark colors or purple to be specific
All three are bad for the environment because all three types release CO2 into the air and have throughout their constant usage helped with creating the greenhouse effect that traps heat and causes global warming. That's why clean energy is a necessity and people are developing harnessing wind and solar power.
As the light intensity increases so does the rate of photosynthesis.
