Focus
One of the things I found most fascinating when I studied biology as an undergradraduate student was our immune system. More precisely the process by which we make specific antibodies that can recognize a seemingly endless number of epitopes. This system seemed so perfect that I did not imagine how an organism could survive without it. It turns out that plants do not have antibodies to defend themselves. This is most remarkable since plants are sessile organisms and therefore cannot escape from pathogens or adverse conditions and yet, many plants can outlive humans, and must therefore fight pathogens as we do.