In this lesson, students work in small groups to analyze and sort a variety of research discoveries. This unit illustrates in part the historical role animals have played in medical research. Students sort these discoveries into several categories, including time period and type of animal included in the research. In this lesson, students work in their groups to answer questions about animals in medical research and to consider which animals might help Chris. Finally, students examine how and why specific animals are selected for research based upon the animal/ organism’s biological complexity and similarity to humans.