You are given a short paragraph, a question and two choices to answer from. Choose the correct answer based on the paragraph and write the answer(not the key).

Q: Paragraph: More pollutants mean poorer air quality.
Question: Michael is studying the air quality of various cities. He finds that there are many more pollutants in the air in Mexico City, than there are in the air of Chicago. Therefore, the air quality will be higher in
Choices: A)Chicago
B)Mexico City

A: Chicago
****
Q: Paragraph: At higher concentrations, particles of reactants are crowded closer together, so they are more likely to collide and react.
Question: Mike is watching how particles of reactants function, and sees that they are very far apart. Considering that the concentration of them is very low, the chance of them colliding together is
Choices: A)high
B)low

A: low
****
Q: Paragraph: By using multiple stages, empty fuel containers could drop away. This reduced the mass of the rocket so that it could fly higher.
Question: David is getting ready to fly into space on a rocket. As the rocket shoots upwards, part of the mass falls away, allowing the rocket to go
Choices: A)higher
B)lower

A:
higher
****