Final answer:
Option d) spleen does not secrete substances that assist the digestive process, unlike the salivary glands, liver, and pancreas which produce saliva, bile, and digestive enzymes respectively.
Step-by-step explanation:
The organ that does not secrete substances that assist the digestive process is d) Spleen.
The spleen is involved in filtering blood and is not directly involved in the digestion of food. On the other hand, the salivary glands secrete saliva that begins the breakdown of carbohydrates, the liver produces bile salts that emulsify lipids, and the pancreas produces digestive enzymes and bicarbonate to aid digestion.