Government Records on voting history and offices held because that is the most likely to be objective instead of biased. A commentators views would be biased. Campaign literature is subjective and could be biased as well. Neighbors and government workers are no source at all because they would be subjective and biased.
It would be the development in agricultural knowledge/technology
Development in agriculture enable hunter/gatherer society to shift their behavior. Before this, they had to keep moving from one place to another in order to seek food to live.
After the development in agricultural knowledge/technology, the society now can stay in one exact place for a long period of time and relied on agricultural product as their main source food.
After living in one same place for a long time, the needs to build things to accommodate their living start to arise. They start to built several things and repeat the process every year. In the end, large cities were developed from the initially small hunter/gatherer society.
Crawford W. Long ( 1815 - 1878 ) was an American surgeon, best known for his first use of inhaled sulfuric acid as an anesthetic. He published his findings in 1849.Sigmund Freud was an Austrian neurologist and the founder of psychoanalysis. Ivan Pavlov was a Russian physiologist, known for his work in classical conditioning.Luis Pasteur was a French biologist who discovered the principles of vaccination and pasteurization.Answer: A . Crawford W. Long
