Answer :
Final answer:
To conduct a valid experiment on the effects of air circulation in a classroom, adding an identical classroom with adjustable windows is the best choice to compare the impact of natural air circulation.
Explanation:
To conduct a valid experiment regarding the effects of air circulation in the classroom, Option C would be the best choice: by adding an identical classroom with adjustable windows.
Adding adjustable windows in the identical classroom allows for controlled changes in air circulation, creating a suitable experimental setup free from external factors like electric fans or closed windows.
By comparing the test scores of the classrooms with and without adjustments to air circulation, it ensures a more accurate evaluation of how natural air circulation affects classroom learning.
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