Agriculture is the cultivation of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the development of civilization. Before sedentary civilizations began, humans were nomadic and had to travel from place to place in order to get food. They had to follow animals to get meat, and had to travel from place to place to forage for grains. If humans had never began to domesticate animals and plants, then we would have never been able to build anything.
Nothing would be able to have been created. Humans would never have been able to do anything but scavenge for food.
It wasn't until the Industrial Revolution in Europe that the population began to rise at a rapidly increasing rate. Before "Modern" Agriculture, people had slowly get enough food to feed themselves and their families. That was the main priority. To feed their families.
Now with Modern Agriculture, people are able to do things other than farming because we have a surplus of food never before seen in human history.