| A | B |
|---|
| 7.5 billion | The human population on Earth is currently over |
| Renewable resources | replaced at a rate faster that we can use them |
| Nonrenewable resources | used faster than they are produced |
| depletion | When nonrenewable resources are used too quickly within a short period of time |
| reduce, reuse, and recycle | the 3 R’s |
| Pollution | any harmful change in the chemical makeup of the soil, water, or air |
| soil | forms when rocks are broken down by weathering |
| water cycle | the continuous transfer of water that maintains our freshwater supply |
| direct harvesting | the destruction or removal of species from their habitats |
| Poaching | illegal capturing and killing |
| habitat destruction | this occurs when people take over land for their own use |
| Deforestation | the destruction of forests resulting from human activity |
| biodiversity | the number of different species that occupy a given area |
| imported species | introduction of a species into an area in which they are not native |
| Industrialization | an economy that relies on machines to produce many products |
| Nuclear fuels | create energy by nuclear fission |
| toxic wastes | poisonous chemicals that come from cities, farms, or industries |
| thermal pollution | Warmer water cannot hold as much dissolved O2 |
| acid rain | This lowers the pH of the soil |
| smog | a combination of smoke and fog |
| greenhouse effect | keeps the Earth warm when little or no sunlight is available |
| global warming | CO2 traps more of the sun’s energy, increasing the overall temperature of Earth |
| CO2 | released when fossil fuels are burned |
| ozone | a special gas in our atmosphere that absorbs harmful UV radiation from the sun |
| CFC’s | The main cause of ozone depletion |
