According to sociologist emile durkheim, is characterized by a simple division of labor and shared religious beliefs such as are found in small agrarian societies.

The answer is "mechanical solidarity".

Mechanical solidarity refers to the social joining of individuals from a general public who have regular qualities and convictions. These normal qualities and convictions constitute an “collective conscience”, that works inside in singular individuals to make them coordinate.

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.