Answer:
A. They cycle elements through the biotic and abiotic components of an ecosystem.
Step-by-step explanation:
Chemical elements such as nitrogen, carbon, phosphorus etc. moves between the living and non-living parts of an ecosystem in the biosphere. The cycle of these elements between these counterparts (abiotic and biotic) is referred to as the BIOGEOCHEMICAL CYCLE.
Firstly, the biotic components of an ecosystem refers to the living organisms such as plants, animals, microbes etc while the abiotic components are the non-living parts such as soil, water etc. Therefore, according to the description given in the options, option A describes what a BIOGEOCHEMICAL CYCLE best.