READINGTECTS THE EARTH FROM HARMFUL FORCES.

7. b.Choice bincludes the main points of the passagephere; the passage encompasses more than that.and is not too broad. Choice afeatures minorChoice c does not mention the atmosphere,points from the passage. Choice calso featureswhich is the main focus of the passage. Choiceminor points, with the addition of History ofdis too narrow—the final paragraph of the pas-the National Park system, which is not includedsage emphasizes that the circulation of thein the passage. Choice dlists points that are notatmosphere is but one example of the complexdiscussed in the passage.events that keeps the Earth alive.