Final answer:
A lack of alertness can indicate early stages of sleep deprivation, which can result in decreased mental alertness and cognitive function.
Step-by-step explanation:
A lack of alertness can indicate early stages of sleep deprivation. Sleep deprivation can result in decreased mental alertness and cognitive function, leading to symptoms such as irritability, cognitive impairment, memory lapses, and impaired moral judgment. It is important to prioritize and maintain adequate sleep to ensure optimal alertness and functioning.