Final answer:
Glucagon is the hormone secreted by the pancreas that signals hunger by lowering blood sugar levels.
Step-by-step explanation:
The hormone secreted by the pancreas that signals hunger by lowering blood sugar levels is glucagon.
Glucagon is released by the alpha cells of the pancreas in response to low blood glucose levels. It stimulates the conversion of stored glycogen into glucose, which increases the level of glucose in the blood.