Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: Energy do ecosystems absorb on the earth.

Answer: What do ecosystems absorb on the earth?


Question: Millibar is the unit used to measure air pressure.

Answer: What is the unit used to measure air pressure?


Question: Respiratory and circulatory systems two systems primarily function to rid the human body of the wastes resulting from cellular energy production.

Answer:
Which two systems primarily function to rid the human body of the wastes resulting from cellular energy production?