Natural selection can only take place if there is variation, or differences, among individuals in a population. importantly, these differences must have some genetic basis; otherwise, the selection will not lead to change in this?

The four Science Regents exams (Earth Science, Living Environment, Chemistry, and Physics) also include separately-scheduled lab practicals.
In New York, students have the opportunity to take Regents Exams in grades 9-12 and, when appropriate, in grade eight.