Final answer:
Decreased blood glucose levels trigger hunger sensations by inducing chemical signals from the pancreas and liver, while increased levels cause insulin release and satiety.
Step-by-step explanation:
The physiological stimulus that will trigger the sensation of hunger is decreased blood glucose levels. When blood glucose levels drop, various chemical signals are generated by the pancreas and liver, which induce hunger and initiate feeding behavior. On the other hand, increased blood glucose levels result in the production of insulin, which facilitates the conversion of glucose to glycogen in the liver, thereby decreasing blood glucose levels and providing satiety signals to the brain.