Which layer of the alimentary canal is exposed to the food we eat and ingest?

The correct answer is: mucosa

The alimentary canal or gastrointestinal tract consist of four layers: mucosa, submucosa, muscular layer and serosa.

Mucosa is the layer that surrounds the lumen, so it is exposed to the food. Mucosa is composed of epithelium (active in absorptive and secretory processes), lamina propria (connective tissue) and muscularis mucosa (peristaltic movement).