What is one of the main differences between the phosphorus and sulfur cycles? a) plants absorb phosphorus mainly from the air and sulfur mainly from the soil. b) animals get phosphorus by eating plants and sulfur from the air they breathe. c) human activities contribute only to the amount of sulfur in the atmosphere but not to that of phosphorus. d) the atmosphere has no significant role in the phosphorus cycle, but is an essential part of the sulfur cycle.

Phosphorus is not abundant in the atmosphere. It comes mostly from the land and ocean. Phosphorus cycle through the lithosphere, hydrosphere, and biosphere, but not the atmosphere. The reason for this is that phosphorus cannot be found in the gas state, unlike the sulfur. On the other hand, sulfur cycle partially occurs in the atmosphere.

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.