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.

Example Input: Question: What type of substance is any matter that has a fixed chemical composition and characteristic properties? Answer: pure chemical substance
Example Output: Pure chemical substance type of substance is any matter that has a fixed chemical composition and characteristic properties.

Example Input: Question: What are four children born at one birth called? Answer: quadruplets
Example Output: Four children born at one birth are called quadruplets.

Example Input: Question: What kind of reaction is a reaction in which two or more substances combine to form a single new substance? Answer: combination reaction
Example Output:
A combination reaction is a reaction in which two or more substances combine to form a single new substance.