【正确答案】 B

【答案解析】[听力原文]11-13
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.

此题是测试原因的推理分析题，根据文中“... 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.”可知人类学会耕种、养家畜是因为打猎不能提供足够食物，而定居生活是开始耕种、养家畜以后改变的生活模式，因此答案是B。