Which of the following best describes non-renewable energy sources?

Non-renewable energy sources are defined as those that are finite and can be depleted over time. These energy sources, such as fossil fuels (coal, oil, and natural gas) and nuclear fuel, exist in limited quantities within the Earth's crust. Once extracted and used, they cannot be readily replaced on a human timescale. This characteristic leads to concerns about sustainability and energy security, as reliance on these sources can result in depletion and the potential for energy crises as reserves diminish.

The other options describe characteristics of renewable energy sources or present inaccurate information. Non-renewable sources cannot be replenished quickly, do not derive from natural processes that occur constantly, and often produce greenhouse gas emissions or other pollutants, which means they do not produce zero emissions. Thus, the most accurate description of non-renewable energy sources is that they are finite and can deplete over time.