People usually have to cany passports to travel from one country to another. But should animals? Groups around the word  are working to create parks that cross country borders. They hope that the parks will help die environment and bring peace and cooperation to neighboring countries. "People draw lines on a map and call them countries," said Steve Thompson of the National Parks Conservation Association. "But animals don' t understand  international  borders. " When animals  are kept in  small  areas,they can spread diseases  more easily. They can also hurt the environment by eating too   many plants and other animals. Allowing animals to cross borders would help improve these conditions,experts say. But that's just one reason why people to create international parks. People have named the parks "peace parks"  because these people believe the parks can help countries learn to work together. The parks create a link between communities and a common desire to learn more about one another. According to Steve Thompson, the parks can "help nations resolve international conflict or even war. " Today there are dozens of peace parks on five continents, The parks play an important role in southern Africa. The Kgalagadi Trausfrontier Park is in the Kalahari Desert in South Africa and Botswana. The countries work together to manage the land and the animals that live there. Other countries ,such as Zimbabwe and Lesotho, are also forming parks. The parks will let animals wander over larger parts of southern Africa, much as they did centuries ago, and it really helps expand elephant and lion populations, which are now damaged by, confinement  in smaller parks. The parks can also help countries attracting tourists and creating jobs. But many issues still remain, such as illegal killing of animals, pollution, and population pressure on the land. Where are the peace parks built?
In mountains In cities Across deserts Across country borders.
Question: People usually have to cany passports to travel from one country to another. But should animals? Groups around the word  are working to create parks that cross country borders. They hope that the parks will help die environment and bring peace and cooperation to neighboring countries. "People draw lines on a map and call them countries," said Steve Thompson of the National Parks Conservation Association. "But animals don' t understand  international  borders. " When animals  are kept in  small  areas,they can spread diseases  more easily. They can also hurt the environment by eating too   many plants and other animals. Allowing animals to cross borders would help improve these conditions,experts say. But that's just one reason why people to create international parks. People have named the parks "peace parks"  because these people believe the parks can help countries learn to work together. The parks create a link between communities and a common desire to learn more about one another. According to Steve Thompson, the parks can "help nations resolve international conflict or even war. " Today there are dozens of peace parks on five continents, The parks play an important role in southern Africa. The Kgalagadi Trausfrontier Park is in the Kalahari Desert in South Africa and Botswana. The countries work together to manage the land and the animals that live there. Other countries ,such as Zimbabwe and Lesotho, are also forming parks. The parks will let animals wander over larger parts of southern Africa, much as they did centuries ago, and it really helps expand elephant and lion populations, which are now damaged by, confinement  in smaller parks. The parks can also help countries attracting tourists and creating jobs. But many issues still remain, such as illegal killing of animals, pollution, and population pressure on the land. Where are the peace parks built?
A. In mountains
B. In cities
C. Across deserts
D. Across country borders.
Answer: