In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.

Q: Question: Terry's system wastes 50% of its energy, while Rick's system wastes 75%. The more efficient system is 
 Answer: Terry's

A: The greater the wasted output energy, the less efficient the system.
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Q: Question: Keely had just run a mile and was now running slower to _____ _____. 
 Answer: cool down

A: When particles move more slowly, temperature is lower and an object feels cooler.
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Q: Question: Terry has two balls and pulls them apart from each other. The gravitational force between the balls 
 Answer: decreases

A:
The gravitational force between two objects decreases as the objects move further apart.
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