Question

What is the difference between nitrogen and phosphorus, based on global cycling?
A. Nitrogen is recycled whereas phosphorus is not.
B. Animals get most of their nitrogen from the water they drink whereas they get their phosphorus from the food they eat.
C. Nitrogen occurs primarily in deep sediments whereas phosphorus occurs primarily in the atmosphere.
D. Nitrogen is lost in the oceans whereas phosphorus is not.
E. Nitrogen has a gaseous phase whereas phosphorus does not.

Answer 1

Hint: The cycling of the nitrogen in the environment from one form to another is known as the nitrogen cycle. The cycling of the phosphorus element in the form of nutrients in the environment is known as the phosphorus cycle. Moreover, both the nitrogen and the phosphorus cycles are types of biogeochemical cycles or nutrient cycles.

Complete answer: Let us look at all the statements that are given to us one by one.
Statement A: Nitrogen is recycled whereas phosphorus is not – In the nitrogen cycle, the atmospheric nitrogen that is fixed by various means like lightning and nitrogen-fixing bacteria is converted into ammonia and various other organic compounds. When the organism dies these nutrients are broken down and the denitrifying bacteria convert the ammonia back to free nitrogen. In the case of the phosphorus, it is taken up by the organisms in the form of the phosphate and it is released back in the same form.
Statement B: Animals get most of their nitrogen from the water they drink whereas they get their phosphorus from the food they eat - The herbivores animals obtain the nitrogen and phosphorus both through the plants that they eat as food. These nutrients are then transferred to the consumers via the food chains.
Statement C: Nitrogen occurs primarily in deep sediments whereas phosphorus occurs primarily in the atmosphere – Nitrogen occurs primarily in the atmosphere in the free form whereas phosphorus occurs primarily in the rocks which are the natural reservoirs of phosphorus.
Statement D: Nitrogen is lost in the oceans whereas phosphorus is not – The nitrogen is found in the atmosphere whereas the phosphorus is lost in the oceans in the form of phosphates.
Statement E: Nitrogen has a gaseous phase whereas phosphorus does not – Nitrogen and phosphorus are both gases so they both possess a gaseous phase.
Thus, based on the above information we can conclude that the difference between nitrogen and phosphorus, based on global cycling is that nitrogen is recycled whereas phosphorus is not.
Hence, the correct answer is option (A).

Note: The biogeochemical cycles or the nutrient cycles are the cycles of the circulation or the exchange of the biogenetic nutrients between the living and the non-living components of the environment. The nutrient passes in the inorganic and the organic form from one organism to another in the food chains and the food webs.