Answer:
Question is incomplete i have added full question with explanation and reaction see attachment.
Make sure the gas cap is on tight. One reason you may not be getting the mileage you expect is because there isn't as much gas in your tank as you think. 147 million gallons of gas were lost last year due to evaporation. Why did it evaporate? The gas cap was not on tight. So just make sure it is tight, and it will enable you to keep all the gas you pay for
The protein in the question can be referred to enzymes since its made of protein. The first statement is the answer
Observation designed to minimize the effects of variables other than the independent variable.
