Why is it a good agricultural practice to plant a field with alfalfa every few years?

Which article of the us constitution addresses the issue of interpeting the laws of the united states

Should the u. s limit the number of terms a lawmaker can serve in congress

For each of the following examples of data, determine which scale of measurement is used. a) the number of miles joggers run per week. b) the starting salaries of graduates of mba programs c) the months in which a firm's employees choose to take their vacations. d) the final letter grades received by students in a math course.