Which process plays an important role in the biogeochemical cycles of carbon, nitrogen, and phosphorus?

The biogeochemical cycles move through mainly the biotic and abiotic components of the earth, more elaborately the spheres -biospheres, lithosphere, hydrosphere and atmosphere regions of the ecosystem. These biogeochemical cycles, from its terminology and discernable word morphology- involves the biological, geological and chemical components that make out to complete an exact and purposed cycle. The purpose in these cycles are to maintain balance and to ensure the ongoing process of the living and non-living organisms in the environment. These cycles’ help to living organisms survive and thrive. One popular example is the water cycle. 

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.