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.

[Q]: Question: What kind of system do echinoderms possess? Answer: water-based circulatory
[A]: Echinoderms possess a water-based circulatory system.


[Q]: Question: What do you call the hard case that surrounds the soft parts of some animals? Answer: exoskeleton
[A]: You call the hard case that surrounds the soft parts of some animals the exoskeleton.


[Q]: Question: Instead of wood, what do some fireplaces use? Answer: propane
[A]:
Instead of wood, some fireplaces use propane.