Enzymes are proteins that are biological catalysts
They reduce the activation energy required for a reaction to occur and thus speed up a reaction
Temperature, above a certain point (optimum temperature) causes them to break down and they are gradually destroyed (denaturing)
They work best at a particular pH (optimum pH) and are once again destroyed by low or high pH's
They have a specific shape, with one particular part, known as the active site, that is specific to the substrate they speed the reaction of. These means they are specific to one type of reaction.
They aren't used in the reaction so they're re-usable.
If it isn't one of these then it is not one of the properties of enzymes
Mucous cells.
This cells primarily produce mucus and are frequently clustered into small glands found usually in the mucus membranes. They commonly lines the proximal and distal portion of the digestive tract. Large number of this cell can found in the mouth which moisten and keep the oral cavity moist. Stomach also have large number of mucous cells which help to protect the organ from the gastric juices it produce.
I believe the answer is A
