The abuts the lumen of the alimentary canal and consists of epithelium

Question is incomplete. Complete question is as follows:

The abuts the lumen of the alimentary canal and consists of epithelium, lamina propria, and muscularis mucosae.

Mucosa

Explanation:

Mucosa or mucosal membrane forms the lining of many cavities in the body like the alimentary canal and also covers many internal organs. It lines reproductive, digestive and respiratory system. In the gastrointestinal tract the mucosa is made of three layers: epithelium, lamina propria and muscularis mucosae.

The epithelium of mucosa is made of simple columnar epithelium cells. It consists of many types of cells like parietal cells (secrete HCL) and foveolar cells (secrete mucus). Lamina propria is a loose connective tissue present beneath the epithelium. It provides nutrition and support to epithelium. Muscularis mucosae has smooth muscle fibers which helps the glands on the surface to secrete their contents and also increase the contact between contents of lumen and epithelium.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.