Stomata open and close primarily due to the action of guard cells that change shape based on their turgidity. In light, guard cells take up potassium ions, causing them to swell and open the stomata. Conversely, in darkness or drought, potassium ions are released, leading to a decrease in turgidity and the closing of the stomata. ;
A device delivering a current of 15.0 A for 30 seconds allows approximately 2.81 × 10^21 electrons to flow through it. First, we calculated the total charge (450 coulombs) and then used the charge of a single electron (1.6 × 10^-19 coulombs) to find the number of electrons. Therefore, n = Q/e results in the given number of electrons.
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