Explain why it matters for plants to open and close their stomata in a daily pattern.
Fig. 2.1 presents the findings from an experiment used to track this rhythm across three days and nights in the plant \textit{Arabidopsis thaliana}. The graph shows the percentage of stomata that are open. In each day there were 14 hours of light (white bar) and in each night there were 10 hours of darkness (black bar). Fig. 2.1 shows that the percentage of open stomata rises during the first seven hours of the experiment. Describe the series of changes in the guard cells that causes stomata to open.
The experiment was repeated with \textit{A. thaliana} plants that remained in darkness from 14 to 96 hours. The outcomes are shown in Fig. 2.2. Using Fig. 2.1 as a reference, explain what Fig. 2.2 shows about how genes and the environment control the rhythm of stomatal opening and closing in \textit{A. thaliana}.