There are quite a few answers to that actually.
1, Its easy to source
2, It reduces greenhouse gasses
3, Lower levels of pollution
I dont have time but write about making something that can help like solar panels
Answer is c. If one essential nutrient within an ecosystem runs out, primary productivity will be limited
According to Vitousek et al., 2010, nutrient limitation defined as meaningful additions of an essential element in biologically available forms which increases the rate of primary productivity or increase in the biomass in an ecosystem. Alternately, nutrient limitation may also explained as when the supply of one essential nutrient of the ecosystem runs out the primary productivity of the plants will be limited.