True or False: The nervous system directs bodily defenses against external stimuli.

The statement is true because the nervous system plays a crucial role in coordinating the body's responses to external stimuli. This includes processing sensory information, integrating it, and generating appropriate responses through various mechanisms. The nervous system is involved in both voluntary actions, such as moving away from a harmful stimulus, and involuntary responses, such as reflexes.

When external stimuli are detected—whether they are potentially harmful (like heat, pressure, or sharp objects) or benign—the nervous system activates appropriate defensive mechanisms, which may include the fight-or-flight response, reflex actions, or other physiological changes. This responsiveness is essential for maintaining homeostasis and protecting the body from harm.

In relation to the other options, the notion that it is dependent on the situation or limited to emergencies does not capture the continuous role of the nervous system in everyday functioning and defecting a variety of stimuli, not just emergencies.