Where is the greatest concentration of salt water? a. by river entry ways b. in the polar zones c. in the temperate zones d. by the equator

The answer is; D

This is due to the fact that temperatures of a solvent are directly proportional to the amount of solute they can dissolve. The waters at the equator get heated more than those of other latitudes due to the angle of sun rays exposure and also the duration. This means that these waters can dissolve more salts per unit volume. As the currents push the waters towards the poles, the waters become cooler and loose some of the dissolved salts by precipitation once the saturation point is reached.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.