Digestion begins when salivary gland secretion enters what?

Mouth

Explanation:

Digestion is the breakdown of food into small pieces that the body can absorb and use. Similarly, the process of digestion begins in the mouth by chewing (mastication). Thus, secretion of the saliva by the salivary gland dissolves some the chewed food and facilitates its passage through the digestive tract.

the water is warmed up by the sun and then it evaporates into the atmosphere. the sunlight warms the water by its heat. water is then cooled down and condensation takes place. the water then finally returns back to the earth by the process of precipitation in the form of rain or ice.

explanation: