I am pretty sure it is something related to space
The earth is made up of many interacting system which are quite dynamic in nature. The earth is sub divided into four components which are THE ATMOSPHERE, THE HYDROSPHERE, THE BIOSPHERE AND THE GEOSPHERE. These are the separate systems that made up the earth system.
The hydrosphere is make up of all the water components on the earth surface and how the water cycle through nature. The atmosphere refers to the layers of gases that surround the planet earth while the biosphere refers to the living components on the earth surface. All these systems interact together to keep life existing on earth.
It could perhaps provide a better understanding of why dinosaurs went extinct. It could also provide some of the things Dino's ate and their average life style.
This is extremely vague, but assuming this is regarding concentration gradient in the nervous system, the Sodium-Potassium pump is responsible for transporting sodium and potassium.