Question

Guano deposits, the excrement of seabirds reptiles and bats are the major source of
A. Phosphorus
B. Sulphur
C. Zinc
D. Nitrogen

Answer 1

Hint: “Guano” is the term applied to the deposition of minerals naturally. These deposits often comprise the carcasses, eggshells and excrement of the dead seabirds. Moreover, guanos can also be defined as the waste products obtained from the excreta of the organisms like cave-dwelling bats, seals or sea birds.

Complete answer:
Guanos are majorly found in the hot and dry climatic conditions having very low or no rainfall and they are also present in the corresponding fertilizers. Classification of guanos has been done on the basis of their chemical composition, geographical origin, genesis and age.
Guanos are excreted in the form of solid due to scarcity of water and are non-soluble and non-toxic. It has a high content of nitrogenous waste therefore it can be used as manure which is proven to be a very effective fertilizer. This will in turn provide the essential nutrients to the growing plants by increasing the content of humus in the soil. Guano birds are known to have high content of nutrients such as ammonium and nitrate.
Thus, the right option is D.

Note: Despite the fact that Guanos offer several advantages over the use of artificial fertilizers, it has not been used as an industrial source of fertilizer. This is because the regeneration time for the Guanos fertilizer is far more as compared to others. Moreover, Guanos are often linked with lower efficiency and challenging mining conditions.