The last option is corrrect because when one species move away from an environment or die it lead to decrease in biodiversity as well as the overall health of ecosystem also decreases.
Answer: <em>The main difference between light and dark reaction is that light reaction is the first stage of photosynthesis, </em>which traps light energy in order to produce ATP and NADPH whereas dark reaction is the second stage of photosynthesis, which produces glucose by using the energy form ATP and NADPH produced from the light