Steel changed people’s lives by making possible the
a. invention of radio. c.development of electricity.
b. construction of skyscrapers. d.establishment of time zones.

- "the past is made of multitudinous items ranging from anything that can be collected, recollected or assessed to originate in the past. as such, the past is a gallimaufry of particulars that may not have been related in any way. however, the human mind seeks organization to understand concepts and other things. the human mind therefore seeks relationships in explaining and studying the past. history being a humanity, dictates that historians have to serve this human trait by bringing structure to details of the past. historians do this by creating interpretive frameworks that capture as many details as possible."

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i also think it is c