Read the passage below and choose one correct answer for each question.

The nomadic life of Mongolian

Mongolian people nowadays still maintain their tradition of a nomadic life. About half of Mongolian population do not settle down but travel from place to place every season. When you think of Mongolian nomads, you think of animal farmers. Their most valuable possessions are their tents and cattle. Mongolia has a severe weather. There are dramatic changed in weather conditions between seasons. That is why Mongolian have to move location throughout the year to the most appropriate spots. In winter, they often move in front of a mountain for shelter. in spring, it’s closer to a river, in summer right next to a river for water supply, and in autumn up a hill to collect hay for winter time. Most nomads move at least four times a year but some might move up to 30 times in a year, especially if they have a lot of animals that eat through the available food quickly.

The number of nomads has, however, significantly decreased over the last years. More and more of its citizens move to Ulaanbaatar because they want to look for an education and a professional job. Mongolia is in a period of rapid change.  

Why do Mongolian have to move location throughout the year?