Final answer:
Glucagon is produced by the alpha cells of the pancreas, and it helps to increase blood glucose levels when they are too low. This hormone is part of the body's homeostatic mechanisms to maintain stable blood glucose concentrations. Option number b is correct.
Step-by-step explanation:
Glucagon is a hormone that plays a critical role in regulating blood glucose levels. It is produced and secreted by the alpha cells of the pancreas, specifically from the pancreatic islets or islets of Langerhans. When blood glucose levels fall, alpha cells release glucagon, which then acts on the liver to convert stored glycogen into glucose, increasing blood glucose levels. Conversely, when blood glucose levels rise, beta cells in the pancreatic islets release insulin to lower blood glucose levels.
Therefore, the answer to the student's question is b. alpha cells. These cells are responsible for producing glucagon, which acts as a counter-regulatory hormone to insulin, helping to maintain the balance of glucose in the blood. This mechanism is part of the body's homeostatic balance and is critical in preventing hypoglycemia, a condition characterized by abnormally low levels of glucose in the blood.