Final answer:
The large intestine's secretions are primarily bicarbonate- and potassium-rich mucus, which helps in fecal movement and intestinal lining protection. Digestive enzymes such as CCK and secretin are active in the small intestine, while bile is produced by the liver and intrinsic factors by the stomach.
Step-by-step explanation:
The secretions in the large intestine are predominantly composed of bicarbonate- and potassium-rich mucus. This mucus, secreted by the goblet cells present in the large intestine, serves to ease the movement of feces and protects the lining of the intestine from the abrasive effects of waste material. It's important to note that digestive enzymes like CCK and secretin are active in the small intestine primarily, where they aid in digestion and absorption of nutrients. Additionally, bile and pancreatic juices are also secreted into the small intestine, specifically into the duodenum, to facilitate the breakdown of fats and neutralize the acidity of chyme.
On the other hand, intrinsic factor is secreted by the stomach to aid in the absorption of vitamin B12. To clarify the given options: Bile is not a secretion of the large intestine; it's produced by the liver and stored in the gallbladder. Digestive enzymes, including CCK and secretin, act in the duodenum of the small intestine, not in the large intestine. Lastly, the intrinsic factor is a secretion of the stomach, not the large intestine.