Final answer:
The sympathetic nervous system is responsible for preparing the body for 'fight-or-flight' responses, while the parasympathetic nervous system helps to conserve energy and assists in 'rest-and-digest' activities. The key difference lies in their functions and responses during stressful versus restful situations to maintain homeostasis.
Step-by-step explanation:
The main differences between the sympathetic and parasympathetic nervous systems revolve around their roles and neurochemicals released. The sympathetic nervous system prepares the body for fight-or-flight situations. It does this by increasing heart rate, redirecting blood to muscles, and releasing adrenaline, among other effects. In contrast, the parasympathetic nervous system promotes a 'rest-and-digest' state, conserving energy by slowing the heart rate, increasing intestinal and gland activity, and relaxing sphincter muscles.
Option (b) 'Sympathetic prepares the body for fight or flight; parasympathetic conserves energy and relaxes the body' is the correct answer. This reflects the balance between the two systems that allows the body to maintain homeostasis. It's a misconception that the sympathetic nervous system solely controls involuntary functions and the parasympathetic regulates voluntary actions. Neither system operates exclusively in either the brain or the spinal cord, nor are they strictly responsible for conscious or unconscious body function control. Also, regarding neurotransmitters, the sympathetic nervous system mainly releases norepinephrine, whereas the parasympathetic releases acetylcholine.