The processes which Calculus illuminates are distributed over an enormous range in the physical sciences, from the motions of the stars to the behavior of nuclear particles; in biological sciences, from basic growth to communication problems; and in the social sciences, from population studies to the theoretical basis for scientific decision making. Calculus can be applied to any problems involving extreme amounts, such as the most, the fastest, the least, or the slowest, which may be described as values for which a certain rate of change is zero.