Blood Glucose Homeostasis Set Point

Steps:

• Recall that the set point is the target level maintained by negative feedback in homeostasis.
• Identify normal fasting blood glucose range as 70-100 mg/dL (noting mg/cm³ likely intends mg/dL).
• Determine the approximate central value or typical set point from physiological references.
• Select the option closest to 80 mg/dL, the standard set point.

Why B is correct:

• The set point for blood glucose is defined as ~80 mg/dL in homeostasis, where insulin lowers and glucagon raises levels to maintain balance.

Why the others are wrong:

• A: 70 mg/dL is the lower limit of normal, risking hypoglycemia if sustained.
• C: 100 mg/dL is the upper normal fasting limit, not the central set point.
• D: 120 mg/dL indicates impaired glucose tolerance or prediabetes.

Final answer: B