Define evolution and give an example. This is for 12th grade biology

Evolution - The gradual change in a species' inherited characteristics, which is driven by the process of natural selection.

Example: Peppered moth

Prior to the industrial revolution, the moths that had light colour thrived but after, those light coloured moths, died due to them being an easier target as they were a light colour against a dark background (from pollution) so the darker moths survived and were able to reproduce.