Renewable resources: a. have finite supplies that will one day be used up. b. include iron, gas, and copper. c. are all living resources. d. can be replenished over months, years, or decades.

Renewable resources can be replenished over months, years, or decades.

Explanation:

As the name suggests, the resources that possess the ability to renew themselves over a period of time (limited to a lifetime) are recognized as renewable resources. These resources are generally found above the 'surface of the Earth' except a few exceptions. They are mainly functional in a cycle that carries itself out at after specific intervals of time. It is due to these cycles that the resources are regenerated. Such cycles of regeneration are not seen in the case of 'nonrenewable resources'.

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