Scientists performed an experiment to determine whether there is a connection between learning ability and food. They took two groups of 20 mice each, all from the same purebred strain. The mice were deprived of food for 3 days and then given a standard learning session in running through a maze. They were trained by giving them a mild electric shock whenever they took a wrong turn. Immediately after each learning session, one group of mice was fed, but the other was not, A week later, all of the mice were tested to see whether they could still run the maze correctly. The group that had been fed had retained this ability, but the other group had not. The probable reason that the scientists used only mice from the same pure-bred strain is so that?

The probable reason that the scientists used only mice from the same purebred strain in this experiment is to minimize the genetic variability between the two groups. By using mice from the same purebred strain, the scientists can ensure that any differences in learning ability and food effects observed are more likely to be a result of the food manipulation rather than genetic differences between the mice. This allows for a more valid comparison between the two groups and increases the reliability of the experiment's findings.