Answer :
Final answer:
The hormone produced by the duodenum that causes an increase in the output of bile by the liver and pancreatic juice rich in bicarbonate ions is secretin.
Explanation:
The hormone produced by the duodenum that causes an increase in the output of bile by the liver and pancreatic juice rich in bicarbonate ions is secretin. Secretin stimulates the pancreas to produce alkaline bicarbonate solution and deliver it to the duodenum. It works in tandem with another hormone called cholecystokinin (CCK), which also stimulates the gallbladder to release bile into the duodenum.