Why did human beings begin to grow crops and raise livestock?

When men lived on this earth thousands of years ago, they lived mainly by hunting wild animals and getting fish from rivers and lakes or even seas if they happened to live near the coast. However, these methods of getting food were very uncertain and often they were not able to get enough to live.
   Men then began to think of more stable ways of getting food. Farming of crops was one. They learnt how to farm the fields and grow crops on which they depended so much. This changed their ways of living.
   Men no longer had to move about from one place to another. Instead they were able to stay in fixed place--usually a suitable spot where they could grow crops, vegetables and even fruits. These places had to be near lakes or rivers where water was easily obtained.
   Gradually, with the passing of time, they became more and more efficient in their farming. Men could produce enough food to feed the people as well as their livestock such as cows, chicken and other domestic animals which provided them with meat. Wheat, fruits and rice were produced for their own use. Com was mainly grown to feed their animals.
   Later, they learnt to live together peacefully, helping one another and fighting better protecting against common enemies.