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).
One example: Paragraph: Many of the worlds people live with water scarcity, and that percentage will increase as populations increase and climate changes.
 Question: John's town used to have lots of water, back when there were only a few hundred people. However, now that the town holds several thousand people, the water availability is 
 Choices: A)scarce 
B)plentiful
Solution is here: scarce
Explanation: Based on the information given in the paragraph, population growth will make water more scarce, so that is the correct answer.

Now, solve this: Paragraph: Warm air is less dense than cool air, so it rises higher in the troposphere.
 Question: If air warms, it becomes _____ dense. 
 Choices: A)less 
B)more
Solution:
less