Answer:
Fossil fuels (non-renewable fuels)
Step-by-step explanation:
Fossil fuels are a natural way of providing energy to the society. They are non-renewable, which means they are not long-lasting. Examples of these are the oil, coal and natural gas. These fuels have been used by humans for many years and have been contributing to the growing problem of global warming. Once these fuels are used, they release carbon dioxide into the atmosphere.
Since fossil fuels are only limited, it poses a threat to be totally consumed in the near future as many societies rely on it. Some societies have already considered switching to renewable resources (wind, water, geothermal, etc.) in order to help our Mother Earth.