Answer:
It also takes brain power—you interpret the letters your eyes see and convert them into words, sentences, and paragraphs. As your brain works hard and your eye muscles tire, it's natural they would need rest, causing your eyes to close as sleep takes over.
Step-by-step explanation:
The most common causes of excessive sleepiness are sleep deprivation and disorders like sleep apnea and insomnia. Depression and other mental health conditions, certain medications, and medical conditions affecting the brain and body can cause daytime drowsiness as well.