Which of the following aids in breaking down food into nutrients needed by the body?

The correct answer is C, as Gastrin, Secretin, and Cholecystokinin (CCK) are hormones that play essential roles in the digestive process. These hormones are involved in regulating the digestive enzymes and bile secretions necessary for breaking down food into absorbable nutrients.

Gastrin stimulates the secretion of gastric acid in the stomach, which is crucial for protein digestion and for creating an acidic environment that activates digestive enzymes. Secretin is released in response to the presence of acidic chyme in the small intestine; it stimulates the pancreas to release bicarbonate, helping to neutralize the acidity and create a suitable pH for enzymatic activity. CCK is released in response to fats and proteins in the small intestine; it stimulates the release of bile from the gallbladder and promotes the secretion of pancreatic enzymes, both of which are key to the digestion of fats and proteins.

Insulin and glucagon, while important for carbohydrate metabolism and blood sugar regulation, do not directly aid in breaking down food into nutrients. They have roles in how the body utilizes nutrients once they have been absorbed, rather than in the initial breakdown of food. Serotonin is primarily known for its role in mood regulation and does not have a direct function in