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.

biological/genetic factors means they were born or predisposed to have something. nothing can really change it, and you can't really do much to "fix" it. it isn't something learned

these are the biological factors:

adrian is relatively tall and he is on the basketball team

(adrian can't ever stop being tall or force himself to be tall. likely one or both of his parents are tall as well and they passed on the tall gene. he probably does basketball because he is tall)

the rest are environmental/cultural factors. these are things that are taught to us. for example, cynthia wasn't born saving pocket money, her family most likely taught her this (environmental factor)

hope this !