Is this right? Please help me

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

How did the russian revolution impact world war i? a) the russians required the allied powers to come to their aid and defeat the radical groups. b) the russians pulled out from the war, enabling the germans to focus on the western front. c) the russians created new technological advancements that were used by the allied powers to win. d) the russians created a new communist government that aligned with the central powers instead.

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.