As human populations grow, human demands for resources like water, land, trees, and energy also grow. Population growth has relatively easy and inexpensive solutions and because population impacts every environmental challenge — it is an essential element to achieve sustainability.
Scout characterizes Boo as a petty criminal and a "malevolent phantom." Jem describes his neighbor as a monstrous figure, six-and-a-half feet tall with bloodstained hands. Dill must imagine Boo based on the descriptions his friends provide him.