A, in urban areas :)
Urban areas have bigger populations than rural ones and the Rocky Mountains have terrain that is difficult to settle on
Answer:
Dense water sinks below less dense water. This is the principle that drives the deep ocean currents that circulate around the world. A combination of high salinity and low temperature near the surface makes seawater dense enough to sink into the deep ocean and flow along the bottom of the basins.
Answer:
This is the best explanation for why there is such a small amount of phosphorus that moves into aquatic systems:
1. Phosphorus is highly stable in the atmosphere and remains there for long periods of time.
Explanation:
The phosphorus first cycle is the process by which the phosphate ion passes in very small amounts through the lithosphere from volcanic aeorosols, then to the hydrosphere, where it stays from 20,000 to 100,000 years in the ocean, and finally to biospherere, where rain and erosion helps washing the phosphorus from the rocks into the soil. So, raining is the beginning of the phosphorus´s second cycle, so it is also, the slowest one of the matter cycles that is why the natural total background phosphate levels in several bodies of freshwater range from 0.005 to 0.05 mg/L. Phosphorus remains mostly on land and in rock and soil minerals.
Although abundant on our planet´s sedimentary rock crust and in human body, phosphorus to commercialize is only found in minerals therefore, phosphates mining activity and calcium heating is the only way to get it in its pure elemental form. It is an essential nutrient for plants and animals and a big percentage of the mined phosphorus is used to make fertilizers.
