Read Paragraph 11 from the passage. With the development of agriculture, the human population grew, thriving on plentiful harvests of wheat and barley. But the area around the grain fields was not good for wild animals. When people cleared a piece of land, the gazelles, red deer, wild boar, and goats that once roamed there lost much of their natural food supply, and so they moved on. As time passed, hunters found fewer and fewer animals to hunt. Hunting had always required great skill. Now hunters needed even greater skill if they wanted to eat meat. What is the author's purpose for including this paragraph in the passage