Your Answer: The two key concepts that drive the process of natural selection are: 1. Variation: Individual variation in an organism's appearance and behavior may be seen in populations of organisms. Body size, hair color, facial features, voice characteristics, and the number of kids are only a few examples of these variances. However, certain characteristics exhibit little or no individual variation. 2. inheritance: Certain characteristics are regularly inherited from parents to children. These qualities are heritable, as opposed to other features that are weakly heritable and are heavily impacted by environmental factors.