To determine what the genotype is, we actually have to conduct experiments, and usually the tools that we use to help us determine what the potential possibilities are for the genotype of any offspring. When we conduct a mating process, this tool is known as a Punnett square. Now, what exactly does a Punnett square tell us? Well, the Punnett square tells us the potential genotypes of that offspring in any given mating process, in any given crossing process. So to see what a punitive square actually looks like let's take a look at the following cross let's suppose we have one parent that is homozygous dominant and the other parent is homozygous recessive so we're mating these two individuals or these two plants or these two organisms in the following way. Now, before they actually mate, what must take place?