50 points to answer these
1. how does carbon enter plants from the atmosphere and how does it ener the soil
2. how does nitrogen return to the atmosphere

1. Carbon can enter plants from the atmosphere if it is attached to oxygen then is taken in by a plant through photosynthesis. It enter the soil if it was in a plant and the leaves are shed or if carbon was in a animal and the animal died so the carbon will be returned to the soil.

2. If bacteria has transform the nitrogen into nitrogen gas