9. Most agricultural fields receive inputs of phosphorus, calcium, and magnesium, which are usually obtained by mining rocks containing those elements, grinding them up, and adding them
to fertilizers. Assess the likely impact of this practice on the demand for certain rocks and on soil dynamics with regards to both a) a nutrient cycle and b) a feedback loop.

There is great impact of this practice on the demand for certain rocks because they are necessary for the higher productivity of crops so their demand as well as price of that rock increases. This practice of adding of nutrients has good effects on soil dynamics as well as on nutrient cycle because these nutrients are not only use by the plants as well as by soil in order to maintain its structure.

A feedback loop is the part of a system in which some portion of the system's output is used as input for future operations. In this situation, the feedback loop is negative because all the materials are used from outside and the output can't be used in the system so we can conclude that this practice has a great impact on the demand of certain rocks.

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