Mastication causes exocrine glands under the tongue and in the back of the mouth to secrete a watery liquid called:

Explanation

Option D is correct. Mastication causes exocrine glands under the tongue and in the back of the mouth to secrete a watery liquid called saliva. Saliva is a complex fluid that contains water, enzymes, and other molecules. It plays a number of important roles in digestion. Saliva is secreted by three pairs of major salivary glands: the parotid glands, the submandibular glands, and the sublingual glands. These glands are located in the head and neck, and they release saliva into the mouth through ducts. When you chew food, the salivary glands are stimulated to produce more saliva. This helps to moisten the food and break it down into smaller pieces. The saliva also contains enzymes that start to break down carbohydrates, such as starch, into smaller molecules that can be absorbed by the body. Saliva is an essential part of digestion, and it helps to keep the mouth healthy. Without saliva, it would be difficult to swallow food, and digestion would be less efficient. The other options are not liquids secreted by exocrine glands in the mouth: a Bolus is a mixture of chewed food and saliva that is formed in the mouth. Bile is a digestive fluid that is produced by the liver and stored in the gallbladder. It is released into the small intestine to help digest fats. Pancreatic juice is a digestive fluid that is produced by the pancreas. It is released into the small intestine to help digest carbohydrates, proteins, and fats.