Đáp án phần 2
We’re only beginning to understand why we sleep to begin with, but we do know it’s ...(11)...essential. ...(12)...Adults need seven to eight hours of sleep a night, and adolescents need about ten. We grow sleepy due to signals from our body, telling our brain we are tired, and signals from the ...(13)...environment telling us it’s ...(14)...dark outside. The rise in sleeping-inducing ...(15)...chemicals, like adenosine and melatonin, send us into a light doze that grows deeper, making our breathing and heart rate slow down and our muscles ...(16)...relax. This non-REM sleep is when DNA is ...(17)...repaired and our bodies replenish themselves for the day ahead.
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