In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: The Boltzmann-Matano method gives coefficients for this process, whose Knudsen type occurs at low pressure. On surfaces, it can occur in reptation and leapfrog modes, while it names an approximation used in reconstruction of optical tomograms. The Bohm type occurs in plasmas, and its constant is related to the ratio of terminal drift velocity to an applied force in the Einstein relation. Multiplying that same constant by 4 and time gives the square of the length associated with this process, whose flux is inversely related to separation in Fick's Laws. For 10 points, name this process also described by Graham's law, the movement of a particle down a concentration gradient
A:
Science