Which of the following is true of sleep?

Lack of sleep can indeed cause decreased mental function. This is well-supported by research that shows sleep is not only essential for physical health but also critical for cognitive processes such as memory, attention, decision-making, and overall mental acuity. When an individual does not get enough restorative sleep, their ability to think clearly, problem solve, and focus diminishes significantly. This cognitive decline can affect day-to-day activities and overall quality of life.

Contextually, while sleep patterns may change with age, indicating that the elderly might experience different sleep challenges, the idea that they fall asleep faster or tolerate sleep deprivation better is not a generally accepted fact. Additionally, while some people claim to function well on little sleep, chronic sleep deprivation is known to have serious consequences on health and cognitive function, making it unrealistic to suggest that one can maintain good health without sufficient sleep over the long term.