The ability to think critically in the presence of arguments with essential quantitative elements, most often graphical elements, will become an essential skill for educated citizens in the future. This paper takes one specific graphical display, a narrow series of observational and interpretational tasks related to a graph, and using a small set…

Investigates high school students' understanding of the physical relationship of chromosomes and genes as expressed in their conceptual models and in their ability to manipulate the models to explain solutions to dihybrid cross problems. Describes three typical models and three students' reasoning processes. Discusses four implications. (YP)