The document provides instructions for a science lab experiment on biotechnology. It explains that scientists use experiments to study cause-and-effect relationships between variables. The independent variable is the factor that is intentionally changed, the dependent variable is the responding factor being measured, and controlled variables are kept constant. Students will use an online virtual lab to study the relationship between European corn borer infestation levels (independent variable) and corn yields (dependent variable). They are instructed to collect data from experiments comparing non-Bt and Bt corn crops at different infestation levels and calculate average yields.