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?

IT eliminated a genetic variable.

A purely non-scientific reason or two:

1. Few people will go without food for three days.
2. Few people will respond well to being shocked electrically.

The probable reason that the scientists used only mice from the same purebred strain is to control for genetic variations and ensure that any observed differences in learning ability and food connection are not due to genetic factors.

By using mice from the same purebred strain, researchers can reduce genetic variation and increase the chances of obtaining more consistent and reliable results. This helps to eliminate the possibility that any observed differences in learning ability could be attributed to genetic differences among the mice.

Using mice from the same purebred strain also allows for better comparison between the two groups of mice - the fed group and the unfed group. It ensures that any observed differences in learning ability are more likely to be associated with the manipulated variable (food deprivation) rather than genetic differences.

In scientific experiments, controlling variables is crucial to accurately determine the effects of specific factors or interventions. By using mice from the same purebred strain, the scientists can better isolate the relationship between learning ability and food deprivation, as they minimize potential confounding factors related to genetics.