Read this passage: it is quite true that the flooding of glen canyon has opened up to the motorboat explorer parts of side canyons that formerly could be reached only by people able to walk. but the sum total of terrain visible to the eye and touchable by hand and foot has been greatly diminished, not increased. because of the dam the river is gone, the inner canyon is gone, the best parts of the numerous side canyons are gone - all hidden beneath hundreds of feet polluted water, accumulating silt, and mounting tons of trash. this portion of glen canyon - and who can estimate how many cubic miles were lost - is no longer accessible to anybody. (except scuba divers.) and this, do not forget, was the most valuable part of glen canyon, richest in scenery, archaeology, history, flora and fauna. in this passage from "the dam-nation of a canyon," what type of bias is the author displaying?