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: Which of the following statements best describes a complex machine? Answer: It is made of more than one simple machine.
[EX A]: A complex machine is described by: it is made of more than one simple machine.

[EX Q]: Question: What play an important role in the modulation of the nuclear chain reaction? Answer: control rods
[EX A]: Control rods play an important role in the modulation of the nuclear chain reaction.

[EX Q]: Question: How many chambers does an amphibian heart have? Answer: three
[EX A]:
There are three chambers in an amphibian heart.