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Which of the following was probably the most difficult challenge facing construction of the railroad?

    which of the following was anecological  result of european exploration from 1400 to 1800?   a.  increased trade with east asia      b.  the spread of epidemic diseases      c.  expansion of english territory      d.  the spread of christianity

Why are slanted roofs found on many buildings within russia and finland? a. to prevent ice slides. b. to prevent the build-up of water during heavy rains. c. to prevent heat from escaping during the clod winter months. d. to prevent snow build-up.