Final answer:
Homeostasis is primarily regulated by the nervous and endocrine systems, so systems like the skeletal system are less involved in maintaining homeostasis.
Step-by-step explanation:
The system that is least involved in homeostasis is not explicitly mentioned in the reference material provided. However, because homeostasis is largely regulated by the nervous and endocrine systems of mammals, we can infer that systems not directly involved in the control and regulation of the body's internal environment, such as the skeletal system primarily providing structure and support, are less involved in maintaining homeostasis. While all systems do play a role to some extent, some like the musculoskeletal system, are not directly involved in the feedback loops that regulate homeostasis.