Water, nitrogen and carbon cycle
The water cycle is driven by solar energy. The sun evaporates the water and the water is returned to the oceans/ lakes. Condensation happens when water is evaporated. This cycle is necessary because it cleans the waters and if water would never evaporate then there would be too much unnecessary water on the oceans and it would be really dirty
The Carbon cycle is how plants transform carbon into oxygen. When we exhale the plants use the carbon we breathe out for photosynthesis and release oxygen. If we didn't have this cycle then we wouldn't have oxygen and the plants wouldn't have carbon and they would die because they wouldn't be able to make food.
The 3 cycles
The atmosphere is 78% nitrogen gas. The nitrogen gas can be put back into the atmosphere by animal waste. There are 4 stages to it, assimilation,ammonia ovation, nitrification and denitrification. We need this cycle because of there wasn't nitrogen in the atmosphere then it would run out.