| A | B |
|---|
| slum | areas of poverty within a city |
| nonrenewable resources | things that cannot readily be replaced in nature, examples are coal and natural gas |
| acid rain | poisonous gases mixed with precipitation |
| greenhouse effect | gases that trap solar energy in the form of heat |
| chlorofluorocarbons (CFCs) | gases used in aerosols, air conditioning, and refrigerators |
| ozone layer | it absorbs most of the sun's radiation, it is essential for human life |
| ozone hole | occurs each year over Antarctica between the months of August and October |
| sustainable development | economic growth that does not interfere with the needs of future generations |
| Green Revolution | A 1970s solution to feeding the world's population |
| renewable resources | Natural elements that can be replenished, an example is water |
