2. The simulation must have a decent number of variables. Figure one and two show two different natural selection simulations using peppered moths. Figure one is good for having students explore the concept of natural selection as applied to peppered moths, but would not be appropriate as an IA as there are very limited variables that can be changed. Figure two, however, could be used as potential IA as the student can change a larger number of variables such as selection pressure, pollution amounts and starting numbers of moths.