Which of these was the main reason andrew johnson was not convicted after he was impeached?

The impeachment of President Andrew Johnson was the result of political conflict and the rupture of ideologies in the aftermath of the American Civil War. It arose from uncompromised beliefs and a contest for power in a nation struggling with reunification.

this isn't a question and if you're going to list things be kind and use commas.

genetics is the study of how dna works, the methodologies defining the new recent technologies allow scientist to have a panoramic view of the entire dna landscape, especially how genomes interact with their environment, including off course, factors outside their organisms.

thus is very possible the existence of both scenarios, where populations of isolated individuals have different genetic traits, and share traits related to genetic mutation, due rats can easily travel overseas using human transport channels. so scientists could get a vast number of data, including human interaction, evolution of rodents, health development, spread of infections, development of new organisms, how genomes evolve in different environments and so on.