What is activation energy? a. energy required by the substrate to fit into the active site b. energy supplied by enzymes in a chemical reaction c. energy released when reactants combine to become products d. energy required to break the chemical bonds of the reactants

energy required to break the chemical bonds of the reactants

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.