Dr. jones discovers that the enamel on a new patient's anterior teeth is mottled and pitted, but the patient doesn't have any caries. most likely, the damage is the result of

Among the following environmental factors, which does not have a long-term impact on the composition of a region's soil? a. kinds of crops grown b. types of fungi present c. topography of the landscape d. variety of species of mammals e. number of freezes occurring annually