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Which four of these developments were made under mongol rule during the pax mongolica? the extension of the grand canal in china the spread of christianity the spread of weapons that used gun powder the invention of new medicines the establishment of a postal system the invention of geometric models of lunar motion

Ahistorian is writing a book about british prime minister winston churchill. she claims that churchill was one of the earliest british leaders to realize that nazi germany was a serious threat to british security what is the best way to determine whether the historian's interpretation is valid? o a. review primary sources to see if churchill ever recorded his opinions of nazi germany. o b. find out whether the historian has written any other books about british leaders. c. analyze secondary sources summarizing the effects of nazi germany on great britain. o d. cite the historian's book in another study about important 20th- century world leaders.

What enabled the drastic increase in us troop development to vietnam between 1964 and 1965?