This investigation focused on the systematic instruction of a science skill from the core content standards in accordance with the Kentucky Alternate Assessment for students with moderate and severe disabilities (MSD). Specifically, this study examined the effectiveness of using a constant time delay procedure with multiple exemplars in teaching the principles of heredity (i.e., transmission of genetic information) to high school students with MSD. In addition, the study assessed whether or not students with MSD could draw conclusions based on meaningful related nontargeted information presented in the consequence of instructional trials during the science lesson and generalize both the target and nontargeted information to novel exemplars. The results of the multiple probe design replicated across five students with MSD show that the procedures were effective. (Contains 5 figures and 3 tables.)