A scientist investigated the effects of morning temperatures on flower width. Which most likely could have been a source of error in his investigation?

A source of error is a factor other than morning temperature that could affect flower width and make the comparison unfair. If the control flowers were a day older than the experimental flowers, their age could influence their width, confounding the results. Recalibrating the calipers and measuring at about the same time each day help improve consistency; not converting units would not affect the comparison if the same units were used throughout.

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