Final answer:
If a natural resource is replaced at a constant rate, regardless of how much is used, it is considered to be non-depletable.
Step-by-step explanation:
If a natural resource is replaced at a constant rate, regardless of how much is used, it is considered to be non-depletable. This means that even though the resource is used, it is continuously replenished at the same rate, making it sustainable in the long term. An example of a non-depletable resource is solar energy, as the sun continuously provides energy to replenish what is used.
Learn more about Types of Natural Resources