What is one way historians can establish the authenticity of a primary source?

comparing the source to other established sources from that time period.

Explanation:

Historians are people who study historical facts and figures to ascertain its authenticity.

A good method of doing so is by comparing the source to other established sources from that time period. When the comparisons are done, the similarities between these primary sources should be established to ensure that the source under review is correct.

it's a secular holiday. it is and was a custom developed to recognize the ending of a time and a wish for a good future. the kind of kiss you exchange, if you are single, is intended to predict what kind of year you will have in the coming year.

it is saying good bye to the last year with all its ups and downs, and hello to the new year, with all its hopes and dreams.