Because of biogeochemical cycling,
a. human activity has no effect on elements, chemical compounds, and other forms of matter.
b. living organisms are not limited by any one nutrient.
c. nutrients are circulated throughout the biosphere.
d. many nutrients do not reach toxic concentrations in the biosphere.

Which best describes the scientific method? a. a path of clearly defined steps that must be followed in a particular order b. a possible answer to a scientific question based on knowledge or research c. the recipe for how to conduct an experiment that must be followed precisely d. the process of hypothesis and testing through which scientific inquiry occurs