Final answer:
Natural selection is a process in which one version of a characteristic is represented in the next generation. It is driven by changes in the environment and leads to the adaptation and survival of species.
Step-by-step explanation:
Natural selection is a process in which one version of a characteristic (or one end of a dimension) is represented in the next generation to either a greater or lesser degree. It is the driving force behind evolutionary change.
For example, in Darwin's finches, the beak size changes as the availability of different-sized seeds changes. Those birds with beaks better suited to the available seeds are more likely to survive and reproduce, passing on their genes for beak size to future generations.
Natural selection is essential for the adaptation and survival of species in changing environments.