Final answer:
Purposeful or preparatory activities such as physical exercise enhance health and regulate homeostasis in the body, which are vital for maintaining life. These activities are part of bodily functions like metabolism and movement. The autonomic nervous system, through its divisions, plays a key role in controlling these functions.
Step-by-step explanation:
The activities—purposeful or preparatory—that are mainly concerned with maintaining or remedying body functions are instrumental in regulating homeostasis and promoting health. Processes like metabolism, growth, responsiveness, and movement are not consciously controlled and are crucial for sustaining life. These processes work continuously to build, maintain, and renew the body's functions. Physical activities, such as physical exercise, play a significant role in enhancing physical fitness and good health by affecting the autonomic system responsible for the same physiological changes associated with the fight-or-flight response.
Furthermore, homeostasis underlies the concept of allostasis, which prepares the body to anticipate future needs. The autonomic nervous system divides its functions between the sympathetic division, which handles the fight-or-flight response, and the parasympathetic division, which promotes rest and digestion. This system, along with the endocrine system, ensures homeostasis for the internal environment based on external stimuli.