Sleep-Cycle Researcher: Modern urban environments expose individuals to artificial light after sunset, disrupting the body's circadian rhythm. Prior to widespread electrification, melatonin release would rise shortly after dusk, promoting earlier sleep onset and deeper sleep cycles. Today, bright indoor lighting and screen exposure delay melatonin production, especially in environments with higher light intensity close to bedtime. In a recent study, researchers observed participants who kept room lights on before attempting sleep. They found that the longer participants were exposed to indoor lighting prior to going to bed, the longer it took for their melatonin levels to rise sufficiently to induce natural sleep. Thus, the study showed that as the ______1______ increased, the ______2______ increased.
Select for 1 and for 2 the phrases that create the statement that most logically completes the passage.
Make only two selections, one in each column.
