In this lab activity from the book Argument-Driven Inquiry in Biology, students use an online simulation (www.fastplants.org/legacy/genetics/Introductions/two-trait.htm) to cross Wisconsin Fast Plants with different traits and identify inheritance patterns, enabling them to analyze data collected over several generations. The simulation offers the opportunity for students to visualize these data, traditionally collected over a long period of time, something that is often difficult for students. After identifying patterns of inheritances, students develop a model that predicts how traits are inherited in these plants. Students test their model by running the online simulations over several generations to determine the validity of their prediction. When students have finished collecting and analyzing data, they develop an argument for their investigation. They prepare a whiteboard presentation that includes the guiding question, claim, evidence, and justification of evidence and present it to the whole class in a round-robin format. After collecting feedback, students return to their original small groups for editing and revising before writing a final report. The book includes an option to extend the lesson by asking students to complete a double-blind peer review of the argument using a rubric provided in the appendix.