Which of the following best describes the principle of evolution by natural selection?
A. Individuals within a population are genetically identical and natural selection occurs randomly
B. Individuals within a population exhibit genetic variation and those that are best adapted to their environment survive
C. Individuals within a population exhibit genetic variation and those that are least adapted to their environment survive
D. Individuals within a population undergo genetic mutation and natural selection occurs randomly
E. Individuals within a population exhibit genetic variation and natural selection occurs randomly