Final answer:
The mucosa is the layer of the alimentary canal lining that absorbs nutrients and secretes mucus.
Step-by-step explanation:
The layer of the alimentary canal lining that absorbs nutrients and secretes mucus is the mucosa. The mucosa is the innermost layer surrounding the lumen, and it consists mainly of the epithelium. The epithelium has the capacity to secrete digestive enzymes and mucus, as well as absorb nutrients and water.