In the context of Mr. Stevenson’s science lesson, what does showing a former student's project exemplify?

Showing a former student's project exemplifies an exemplar of quality work because it serves as a concrete reference point for current students. By presenting this example, Mr. Stevenson is able to illustrate the standards of excellence that he expects from his students. This tangible piece of work can motivate students, help them understand the expectations of the assignment, and provide them with inspiration for their own projects. It sets a benchmark, demonstrating what successful completion might look like, thus guiding students in their learning process and encouraging them to achieve similar quality in their own work.