Barry knew Alice was tired, but he was surprised that the argument between their three-year-old twin boys did not awaken her. She had not been asleep very long and occasionally changed her position, but did not wake. Alice is probably in: (Points: 5)
stage 2 sleep.
stage 3 sleep.
stage 4 sleep.
REM sleep.
I believe it is stage 3
To determine the stage of sleep Alice is in, we need to understand the different stages of sleep and their characteristics.
There are four stages of sleep: stage 1, stage 2, stage 3, and REM (rapid eye movement) sleep. Each stage is distinguished by specific brain wave patterns and physiological changes.
Stage 1 sleep is the lightest stage and occurs as you transition from being awake to falling asleep. During this stage, your brain produces theta waves, and muscle activity begins to decrease. It is easy to awaken someone from stage 1 sleep.
Stage 2 sleep is a slightly deeper stage than stage 1. During this stage, brain waves become slower with occasional bursts of rapid brain activity known as sleep spindles. Breathing and heart rate also start to decrease, and it becomes harder to wake someone up.
Stage 3 sleep, also known as slow-wave sleep or deep sleep, is characterized by the presence of delta waves in the brain. It is the deepest stage of non-REM sleep. As the name suggests, this stage involves slower brain wave activity, and it is difficult to wake someone up during this stage.
REM sleep is the stage in which most dreams occur. It is characterized by rapid eye movements, increased brain activity, and vivid dreams. The body is temporarily paralyzed during REM sleep to prevent acting out dreams.
Based on the information given in the scenario, since Alice was able to occasionally change her position without waking up, it is unlikely that she is in REM sleep, as muscle paralysis occurs during this stage. Additionally, REM sleep typically occurs later in the sleep cycle.
Considering that Alice hadn't been asleep very long and the argument between their twin boys didn't awaken her, it is highly likely that Alice is in stage 2 sleep. Stage 2 sleep is deeper than stage 1, but not as deep as stage 3, making it more likely for someone to sleep through disturbances or noise in this stage.
In conclusion, based on the information provided, it is most probable that Alice is in stage 2 sleep.