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: What occurs when an unstable nucleus emits a beta particle and energy? Answer: beta decay
[EX A]: Beta decay occurs when an unstable nucleus emits a beta particle and energy.

[EX Q]: Question: Through what system of the body do hormones generally travel? Answer: circulatory system
[EX A]: Hormones generally travel through the circulatory system system of the body.

[EX Q]: Question: What is greatest source of hazardous waste? Answer: industry
[EX A]:
Industry is the greatest source of hazardous waste.