Ascientist wants to study the effects of morning temperatures on flower width. which is most likely a source of error in this scientific experiment?

The flower width data were collected at about the same time every day.  

According to the research, the responder made with the same query as this question it is:

1.        The flower width data were collected at about the same time every day.
Why this choice because, the study is delving into the effects of morning temperatures on flower width hence, if the scientists collect flower at the same time –hour or minutes everyday during the period of the study the variable of time is not allotted from sunrise period to high noon since it defines time as morning, the variant of time is only inapt.