What are I~"echnrica.~'t nutrients? \\__."_ a) nutrients formed formed from technical process waste by-products \\___.3' b) strictly limited to non-toxic, non-harmful synthetic materials that have no negative effects on the natural environment; they can be used in continuous cycles as the same product without losing their integrity or quality Li} C) strictly limited to non-toxic, non-harmful synthetic materials that have no negative effects on the natural environment; and they cannot be used in continuous cycles as the same product without losing their integrity or quality. ___.:' d) strictly limited to toxic, harmful synthetic materials that have negative effects on the natural environment; they can be used in continuous cycles as the same product without losing their integrity or quality