Answer:
mouth
Step-by-step explanation:
"Digestion" refers to the breakdown of food from big molecules to small molecules. It immediately starts in the mouth, which is part of the first step called "Ingestion." Food enters the mouth and is masticated with the help of the teeth. This starts the chemical breakdown of carbohydrates. The food then becomes moistened and dissolved, which helps propel it towards the pharynx. It is lubricated here and brought to the esophagus.