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).

[EX Q]: Paragraph: As the distance between the objects increases the magnetic force of attraction decreases.
 Question: Lisa is hitting a tennis ball against the wall. As the tennis ball bounces towards the wall and away from her, the magnetic force of attraction between the wall and the ball 
 Choices: A)increases 
B)decreases.
[EX A]: increases

[EX Q]: Paragraph: At higher concentrations, particles of reactants are crowded closer together, so they are more likely to collide and react.
 Question: Ian sees an object with few colliding particles, and he compares it to another object with few colliding particles. Which is true about the objects? 
 Choices: A)the object with many colliding particles has a lower concentration of particles 
B)the object with many colliding particles has a higher concentration of particles
[EX A]: the object with many colliding particles has a lower concentration of particles

[EX Q]: Paragraph: A: As the car approaches the radar gun, the reflected microwaves get bunched up in front of the car. Therefore, the waves the receiver detects have a higher frequency than they would if they were being reflected from a stationary object. The faster the car is moving, the greater the increase in the frequency of the waves.
 Question: The cop shot the radar gun at the super slow car, which _____ the waves. 
 Choices: A)increased 
B)decreased
[EX A]:
decreased