AP BIOLOGY

Detailed explanation-1: -Chromosome number is not a factor that influences natural selection. The other three choices represent factors that drive the process of natural selection. Random mutations in DNA provide genetic variation in a population of species and allow for natural selection to occur.

Detailed explanation-2: -There are four principles at work in evolution-variation, inheritance, selection and time. These are considered the components of the evolutionary mechanism of natural selection.

Detailed explanation-3: -Natural selection occurs only if there is both (1) variation in the genetic information between organisms in a population and (2) variation in the expression of that genetic information-that is, trait variation-that leads to differences in performance among individuals.

Detailed explanation-4: -Natural selection is a simple mechanism that causes populations of living things to change over time. In fact, it is so simple that it can be broken down into five basic steps, abbreviated here as VISTA: Variation, Inheritance, Selection, Time and Adaptation.