Final answer:
Ruth's set-point weight is 130 pounds, and after pregnancy, her body returned to this weight through the process of homeostasis.
Step-by-step explanation:
For Ruth, 130 pounds is a(n) set-point weight, and her body went back to it through the process of homeostasis. The concept of set-point weight suggests that each individual has an ideal body weight that is genetically predetermined and resistant to change. With the additional metabolic demands of pregnancy and breastfeeding, Ruth's body temporarily adjusted to support her growing fetus. However, following pregnancy, her body naturally regulated its systems, leading her to return to her set-point weight through homeostasis, which is the process by which the body maintains a stable internal environment in the face of external changes.