Final answer:
Bicarbonate is known as nature's antacid because it is secreted by the pancreas to neutralize the highly acidic chyme in the duodenum during digestion.
Step-by-step explanation:
The correct answer is B) Bicarbonate.
Bicarbonate is known as nature's antacid because it is secreted by the pancreas to neutralize the highly acidic chyme in the duodenum during the digestion process.
When chyme enters the duodenum, a hormone called secretin stimulates the pancreas to produce alkaline bicarbonate solution and deliver it to the duodenum.
This helps to balance the pH and regulate the digestive process.