Before the development of writing what technique was used to preserve stories about the past

d. periodization. they used years or time lines with b.c. or b.c.e. or ad, ad being now, ex. 2018 is 2018 ad

a historian researching the immigration policies of the early 1900s would expect a source written today,rather than in 1910 to :

( a ) be more interested in objective data and statistics.