It is refreshing to read a book about our planet by an author who does not allow facts to be (i)____________ politics: well aware of the political disputes about the effects of human activities on climate and biodiversity, this author does not permit them to (ii)____________ his comprehensive description of what we know about our biosphere. He emphasizes the enormous gaps in our knowledge, the sparseness of our observations, and the (iii)____________, calling attention to the many aspects of planetary evolution that must be better understood before we can accurately diagnose the condition of our planet. A. overshadowed B. enhance C. plausibility of our hypotheses D. invalidated E. obscure F. certainty of our entitlement G. illuminated H. underscore I. superficiality of our theories