| A | B |
| fossil fuel | fuel such as coal and natural gas that comes from organisms that lived long ago |
| global warming | an increase in the Earth's average temperture due to increase in Carbon dioxide |
| nonrenewable resource | a resource that, once used, cannot be replaced |
| ozone layer (ozone shield) | a layer of ozone gas in the atmosphere that block some UV radiation from the sun |
| pollution | a harmful change in the soil, air or water |
| renewable resource | a resource that, given time, can be replaced |
| nuclear fuel | an alternative to fossil fuels and renewable resources, a source of radioactive waste |
| radiation | released energy, can cause DNA mutation and cancer |
| natural disaster | a natural event that greatly damages an ecosystem |
| sustainability | having the ability to last |