Increasing heart rate and force of contraction when blood pressure falls.
Secreting insulin after a meal to return blood sugar concentration to normal.
Retention of fluid leads to retention of more fluid.
Shivering when body temperature falls below normal.
This is because it is an example of a positive feedback loop, which amplifies the change and moves the system away from its normal state.
A negative feedback loop is a mechanism that reverses a deviation from the set point and maintains homeostasis.
Choice A is wrong because increasing heart rate and force of contraction when blood pressure falls is a negative feedback loop that restores blood pressure to normal.
Choice B is wrong because secreting insulin after a meal to return blood sugar concentration toward normal is a negative feedback loop that regulates glucose levels.
Choice D is wrong because shivering when body temperature falls below normal is a negative feedback loop that increases heat production and raises body temperature.
Normal ranges for blood pressure are 90/60 mmHg to 120/80 mmHg, for blood glucose, are 70 mg/dL to 140 mg/dL, and for body temperature are 36.5°C to 37.5°C or 97.7°F to 99.5°F.