Answer:
The dark colored moths were due to a genetic mutation, and were more than likely present before the Industrial Revolution. Their fitness was low because predators could easily see them on the light-colored trees. They would be eaten before they could reproduce and pass on their genetic mutation. After the trees became darkened by soot, the darker colored moths now had the survival advantage, able to "hide" from predators. The lighter colored moths became more visible to predators, and the advantage shifted. Now, the light colored moths were more visible to predators, were eaten, and didn't have the chance to reproduce. The darker moths with the mutation had the survival advantage, blending in with the soot-covered trees, and were able to reproduce at higher rates, passing the mutation on to later generations.
Answer - Cyanobacteria aka Algae that contributed in creating O2 for the atmosphere as a byproduct thru Photosynthetic.
Reason - Of course Algae make up mainly the whole world in waters and they do photosynthesis to give off oxygen in the atmosphere.
