What does the sympathetic nervous system control in response to fear-inducing stimuli?

The sympathetic nervous system is responsible for the body's rapid involuntary response to stressful or fear-inducing situations, commonly referred to as the "fight-or-flight" response. When activated, this system prepares the body to either confront or flee from a perceived threat.

One of the primary effects of sympathetic activation includes heightened alertness, which sharpens senses and enhances awareness of the environment. This heightened state of vigilance is crucial for making quick decisions in dangerous situations. Additionally, an increase in heart rate is a physiological change that helps pump more blood, delivering oxygen and nutrients to muscles, which is essential for quick movement.

Thus, the correct answer accurately captures the key physiological changes facilitated by the sympathetic nervous system in response to fear, emphasizing increased alertness and a faster heart rate as part of the body's adaptive mechanisms in stressful situations. The other options do not accurately reflect the acute physiological changes that occur during sympathetic activation.