Final answer:
The false statement is that levels of consciousness are not related to brain function. Consciousness is closely linked to brain activity, with stimuli affecting awareness.
Step-by-step explanation:
The statement among the options provided that is FALSE is "Levels of consciousness are not related to brain function." Levels of consciousness are indeed related to brain function; various stimuli, both internal and external, affect our awareness and the brain is central to processing these stimuli. The Glasgow Coma Scale is indeed used to measure levels of consciousness, drugs or alcohol can affect those levels, and a person's behavior and response to stimuli are indications of their current state of consciousness.