Final answer:
The endocrine system and the autonomic nervous system are primarily responsible for maintaining homeostasis, working in conjunction to balance bodily functions.
Step-by-step explanation:
The two major systems bearing the main responsibility for homeostasis are the endocrine system and the autonomic nervous system. The endocrine system releases hormones that regulate processes throughout the body, maintaining balance and proper function.
The autonomic nervous system operates through two divisions: the sympathetic division, responsible for the fight-or-flight response, and the parasythetic division, which promotes rest-and-digest activities. These systems work together with other organ systems like the circulatory and respiratory systems to maintain the body's internal conditions within optimal ranges.
Homeostasis is a state of equilibrium essential for the proper functioning of biological systems and is influenced by both internal and external changes.