Answer the questions about supporting details that follow the textbook passage. 1The climate becomes colder when the amount of dust at high altitudes in the atmosphere increases. 2There are several ways that dust may get into the atmosphere. 3Volcanic eruptions can add so much dust that sunlight is scattered back to outer space. 4Chimneys, especially industrial smokestacks, also throw large amounts of dust into the atmosphere. 5The burning of tropical forests to clear land for fanning is another way the amount of airborne dust is increased. 6Finally, should a nuclear war ever occur, it might add so much dust to the atmosphere that it could cause a new ice age-a nuclear winter in which the climate becomes so cold that no new crops can be grown.