Answer :
Final answer:
Secretin is the hormone responsible for stimulating the pancreas to release bicarbonate-rich pancreatic juice, which neutralizes the acidity of chyme in the duodenum.
Explanation:
The hormone that causes an increased output of bicarbonate-rich pancreatic juice is secretin. Secretin is released in response to the entry of acidic chyme into the duodenum. This hormone then stimulates the pancreas to produce and release an alkaline solution rich in bicarbonate to neutralize the acidic chyme. This action is crucial for protecting the intestinal lining and providing the proper pH for digestive enzymes to function effectively.