Question

ASSERTION: The phosphorus cycle is an imperfect cycle as a sufficient amount of phosphorus combines with ${Al^3+}$, ${Fe^2+}$ and ${Ca^2+}$ to form insoluble and unavailable salts.
REASON: Phosphate circulates in the abiotic environment in the lithosphere as well as the atmosphere.
(a) Both assertion and reason are correct and the reason is the correct explanation for assertion.
(b) Both assertion and reason are correct but the reason is not the correct explanation of assertion.
(c) Assertion is correct but the reason is incorrect
(d) Both assertion and reason are incorrect

Answer 1

Hint: Phosphorus cycle circulates between the abiotic and biotic components and takes place sedimentary. In soil after the weathering of rock, the soil locks some minerals which get uptake by the producers and some minerals runoff.

Complete answer:
In the phosphorus cycle, the soil consists of the minerals from rock by weathering and the detritus of animals and plants. The metals like iron, calcium and aluminium phosphate get locked into the soil and by the increase in the acidity and alkalinity the solubility decreases and the metal remains in insoluble and salt form.
The phosphorus cycle takes place in both the lithosphere and hydrosphere. Therefore the cycling pool in the phosphorus cycle is in the soil and water, not in the air. In the lithosphere, the organic and inorganic phosphates break down where the organic phosphate gets used up by the higher plant whereas the inorganic one remains in the soil. In the hydrosphere, the metal phosphate gets dissolved in the soil and settles down in the form of a deposit. Some phosphate is used up while some remain as it is. The phosphorus gets retrieved from the soil through fishing, collection of seaweeds. Due to the presence of insoluble metal phosphate and undecomposed dead remains in the soil and undegraded sediment in the water, the phosphorus cycle is considered the imperfect cycle.

Note:
The replenishment of phosphorus cycle takes place by use of guano deposit near several islands, dredging of the lake bed, industrial effluents and by the addition of phosphate fertilizers obtained by the mining of phosphate rocks.