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Across 4. The probability that a particular adverse effect will result from some exposureor condition. 5. Study of contaminants in the biosphere, including their harmful effects on ecosystems. 6. The way a scientist approaches a problem by formulating a hypothesis and then testing it. 8. A city with more than 10 million inhabitants 10. Disease that reaches nearly every part of the world and has the potential to infect almost every person. 11. Condition in which people live with chronic hunger and malnutrition. 12. An estimate of the expected increase in cancer associated with a unit increase in exposure to a chemical. 14. Adverse effect that occurs within a short period after exposure to a toxicant. 15. Condition in which people cannot meet their basic needs for adequate food, shelter, water, etc. 16. A condition that has potential to cause harm. 17. A chemical with adverse huamn health effects. 18. Economic development that meets the needs of the present generaton without compromising future ones. 19. Disease that is constantly present, although often varying in prevelance in a region or population.

Down 1. Adverse effects that occur some time after exposure to a toxicant or after extended exposure. 2. A person who values natural resources due to their usefulness for practical purposes but uses them carefully 3. The human use of materials and energy. 5. Branch of bilogy that studies interelatioships between organisms and their environment. 7. The nmuber and variety of Earth's organisms. 9. The buildup of a persistent toxic substance in an organisms body. 13. A natural system consisting of a community of organismsand its physical environment.