Carbon, Nitrogen, Phosphorus
The carbon cycle is a process by which carbon is cycled between the atmosphere, land, water, and organisms.
The carbon cycle is very important. We burn the fossil fuels and release them into the atmosphere. The carbon then returns to the atmosphere as carbon dioxide. Power plants, factories and cars rely on fossil fuels to operate.
The nitrogen cycle is a process in which nitrogen is cycled between the atmosphere, bacteria, and other organisms.
Nitrogen is an important factor in organism's ability to create proteins which are used to build new cells. They are a major factor in the homeostasis of organisms.