Gregory Had Gas uses humor to show children two key things. First, that they are (or become) what they eat; and second, that their dietary choices impact the natural world. By ingesting jellybeans tossed into his no longer pristine pond, Gregory inadvertently invents jet-skiing for frogs The hot air that builds up inside him from the uncustomary food fare has Gregory "bio-locomoting" across the pond fueled by (the release of) his own hot air The author, a former English teacher, has also included a convenient vocabulary list to assist young readers in their reading comprehension skills.