Which body organ produces the hormone insulin?

The pancreas is the organ responsible for producing the hormone insulin. Insulin plays a critical role in regulating blood glucose levels by enabling cells to absorb glucose from the bloodstream and use it as energy or store it for future use. The pancreas contains specialized cells known as beta cells, which specifically synthesize and secrete insulin in response to rising blood sugar levels, such as after eating.

In contrast, the other options are involved in different roles within the body. The kidneys filter blood and create urine but do not produce insulin. The liver has a role in metabolizing carbohydrates, including storing glucose as glycogen and converting it back to glucose when needed, but it does not produce insulin. The gallbladder functions primarily in storing bile produced by the liver, which aids in digestion but is not involved in insulin production. Understanding the specific function of each organ helps clarify why the pancreas is the correct answer.