What defines a non-renewable resource?

A non-renewable resource is defined as one that cannot be replaced easily or within a human timescale. This means that once it is used up, it takes a significant amount of time—often millions of years—for new deposits to form naturally. Common examples include fossil fuels like coal, oil, and natural gas, as well as certain minerals and metals.

While renewable resources are those that can be replenished over relatively short periods through natural processes, such as solar energy, wind, and biomass, non-renewable resources do not have the same capacity for replenishment on a human timescale. This understanding highlights the importance of conservation and the sustainable management of non-renewable resources, as reliance on them can lead to depletion and environmental challenges. Other options are not appropriate definitions: reusability and natural replenishment speak to renewable resources, while availability does not define a resource's renewability.