The climax communities are the communities that have reached equilibrium. This basically means that there's the optimal number of species of flora and fauna, as well as the optimal populations of them in the ecosystem. They all interact and are perfectly adapted to coexist, benefit from one another, and balance the usage of food sources with its renewing. This type of communities appear at places where there has been no disturbances for quite some time, so the species lving there managed to create a perfect balance.
the moon would have to be closer to the earth for it to perfectly align with the sun, or if it were smaller it would look like a circle with a smaller black circle in the middle.
