The Cycle of Life

Think about the planet earth. How do you balance all the animals living on this planet? There's like hundreds of thousands of different species. And then there's billions of humans on this planet. This has to be balanced out because otherwise it couldn't be sustainable. Otherwise all the plants would die because they wouldn’t have enough of the gases they need. If the planets were not perfectly balanced with the gravitation of the sun and also their moons and all the other planets in our solar system, then they would quickly deorbit.