Question

how do the plants contribute in the nitrogen cycle, oxygen cycle, carbon cycle, water cycle.

Answer 1

In nitrogen cycle some blue green algae are turning ammonia into nitrates and nitrite.
Oxygen cycle plant take co2 from atmosphere and turn into O2
In water cycle plants roots help in perforation of water but some water is used by plant and water from leaves evaporates (Transpiration)
In carbon cycle plant takes co2 when plant dies it turns into fossil fuel and when it burn it turns into co2