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fossil fuel – n. a fuel, such as coal, oil, or natural gas, that is formed in the earth from dead plants or animals
emit – v. send out gas, heat, light, etc. into the air
grab – v. take hold of something
degradation – n. a worsening of quality
challenge – n. a difficult task or problem : something that is hard to do
renewable – adj. any naturally occurring source of energy, such solar or wind
loop – n. the repeating of something over and over
