Now, we know that the colors of our eyes varies from one individual to another individual. Someone might have hazel eyes another person might have blue eyes or green eyes or gray eyes or brown eyes. So we have many different types of variations for that particular trait and that's precisely what makes that trait highly variable in humans. And in the same analogous way, these pea plants also contain traits that vary from one plant to another plant and thus they're highly variable. Now, what traits did he actually study? Well, some of these traits are listed on the board.