Marjorie is conducting a science experiment to measure the amount of pollution produced by cars that used gasoline containing different amounts of lead. Identify the dependent and independent variables.
a: i= conducting a science experiment
d= the amount of pollution
b: i= the amount of pollution
d= gasoline containing different amounts of lead
c: i= gasoline containing different amounts of lead
d= type of car
d: i= gasoline containing different amounts of lead
d= the amount of pollution