: "University students take these classes to satisfy their science distribution requirement."
: Please tell me, what is a "distribution requirement"?
Probably what was called a breadth requirement when I was a student. Every student who isn't majoring in a scientific subject is required to take a few courses in science in order to graduate. The student's course credits are "distributed" (spread out) among different disciplines.
Similarly, science majors have to take some courses in history and so forth.