The Köppen classification system for climate is widely used because ________.
◦ it is easy to use, and it covers the most affluent parts of the world, including Europe, the U.S. and north Africa
◦ it uses easily obtained data and can cover a large area with a single classification
◦ it is a highly evolved classification system that has been carefully refined and improved over more than a century so that it meets the complex needs of a modern society
◦ it is easy to use, and it covers the most populated areas of the earth and the oceans
◦ it uses easily obtained data, and the system is relatively clear