why is the linner wall of alimantary canal not digisteg although the digestive enzymes can digest all the materials that make cell?

There are no options to this question but it can be answered by giving a general explanation. The answer is:

Because the digestive enzymes are not in direct contact with the cells that make up the walls of the alimentary canal. The walls are protected by mucuous lining.

Explanation:

Digestion of our ingested food is an important process for the effective functioning of our body system. Digestion is the process whereby food, which are usually macromolecules, are broken down into simpler molecules usable by the body. After food is taken in from the mouth (ingestion), it must be broken down by chemical and mechanical means.

The chemicals means is through digestive enzymes, which are proteinous chemical substances. The digestive system consists of the alimentary canal or digestive tract, which is a tube-like organ that forms the path for food passage. Since digestive enzymes secreted during digestion can disintegrate every macro biomolecule e.g protein, carbohydrate etc, it can also break down the molecules that make up the cells of the tract wall.

However, the digestive enzymes does not break down the cells of the canal's wall because the body system secretes mucus, which lubricates the passage of food along the canal. It also prevents the digestive enzymes from coming in contact and acting on the macromolecules that make up the cells of the walls of the alimentary canal.

the fossil record provides evidence of a common ancestor to many species.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.