Which of the following best defines a renewable energy source?

A renewable energy source is defined by its ability to regenerate naturally and its sustainability over time. This means that, unlike non-renewable energy sources such as fossil fuels, which can be depleted, renewable sources like solar, wind, hydro, and geothermal energy are continually replenished by natural processes. For instance, the sun provides a constant supply of solar energy, and the wind continues to blow, making these sources reliable and sustainable options for energy production.

The other choices do not accurately capture the essence of renewable energy. Non-renewable resources are inherently limited, and their reliance would exclude the definition of renewability. The notion of generating immediate profits is not an inherent characteristic of renewable sources; profitability can vary based on market conditions, technology, and infrastructure. Extensive mining operations are often associated with non-renewable resources, and the environmental impacts of such operations contrast sharply with the principles of sustainability inherent in renewable sources. Thus, the definition encapsulated in the correct choice highlights the core attributes of renewable energy: self-replenishment and sustainability.