Answer:
Started in China it spread through people that went to visit other places or items that were manufactured there were contaminated
The carbon(C) and oxygen(O2) is the reactants and carbondioxide(CO2) is the produce
A HEV has an engine that uses electric power as well as gasoline to move. When using the electric motor, there are no CO2 emission from the car. So the overall emission should be lower on a HEV than on a purely gasoline car, since you can choose to only use electric power.
