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).

Paragraph: For a given medium such as air, sound has a slower speed at lower temperatures.
Question: If Mary is blowing an air horn underwater and she lowers the temperature of the water, what will happen to the speed of the sound waves generated by the air horn?
Choices: A)increase
B)decrease
decrease

Paragraph: At higher concentrations, particles of reactants are crowded closer together, so they are more likely to collide and react.
Question: DJ has a solution that he adds particles to. The solution is now a _____ concentration.
Choices: A)higher
B)lower
higher

Paragraph: At higher temperatures, particles of reactants have more energy, so they move faster. They are more likely to bump into one another and to collide with greater force.
Question: A particle that is in the desert is likely _____ compared to one in the arctic.
Choices: A)faster
B)slower
faster