The First Agricultural Revolution, also known as the Neolithic Revolution, is the transformation of human societies from hunting and gathering to farming. This transition occurred worldwide between 10,000 BC and 2000 BC, with the earliest known developments taking place in the Middle East. Wheat was the first cereal grown and it was in the middle east.
The second agricultural revolution occurred during the industrial revolution which was in the 17th and 18th century and created a time of improvements to Great Britain, the Netherlands, Denmark, and other neighboring countries. Farming techniques were changing as the machinery grew. The farmers were now producing enough food to feed thousands of people instead of just their families.
The 3rd agricultural revolution occurred during the 1900s when farmers were trying to eliminate hunger. New practices were performed which allowed farmers to produce more of the same thing with the same amount of land that they had before. The problem now wasn't that there wasn't enough food, it was how do we spread it across the population. Giving food to the people who need it is the only way of doing that because an increase in the production line doesn't solve anything.
Genetically modified organisms is where DNA from one animal is put into another species creating different genes. The animal is grows quicker and becomes bigger which means more food out of one animal. This changes farming by less animals needed and they don't need to raise the animals anymore. Pros from this is that it's quicker and there is more meat out of the animal. Cons are that the animals are treated harsh and some can't even walk because there muscles can't support their own weight.