In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

[EX Q]: Question: During an earthquake, wet soils become like what? Answer: quicksand
[EX A]: During an earthquake, wet soils become like quicksand.

[EX Q]: Question: What type of transport requires no energy and occurs when substances move from areas of higher to lower concentration? Answer: passive transport
[EX A]: Passive transport requires no energy and occurs when substances move from areas of higher to lower concentration.

[EX Q]: Question: What part of the atmosphere is the heat source? Answer: stratosphere
[EX A]:
The stratosphere is the heat source.