9781422273890

Sleep gives your brain the opportunity to process everything that happened during the day.

WORDS TO UNDERSTAND

antibodies: proteins in the blood that fight off viruses and bacteria cardiovascular: relating to the heart and circulation degenerative: describes a disease that causes increasing damage over time innate: inborn or natural narcolepsy: a disorder in which someone can fall into deep sleep at any moment progressive: something that moves ahead step by step

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