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