Which best describes copper?

Copper is best described as a naturally occurring element because it is found in nature in various forms and is essential for many biological processes. As a metal, copper is a key nutrient in soil and water systems and plays a significant role in the metabolic processes of plants and animals. It can be mined and extracted from ores, making it an integral part of many ecosystems.

The other classifications, such as synthetic, organic, or radioactive, do not accurately apply to copper. Synthetic substances are man-made, organic compounds contain carbon and are derived from living organisms, and radioactive materials emit radiation due to unstable atomic nuclei. Copper, however, is a stable, naturally derived metal with multiple beneficial applications, particularly in agriculture and water treatments.