| A | B |
|---|
| scratch testing | determining the hardness of a mineral by scratching one mineral with another. |
| carbon cycle | the movement of carbon through the atmosphere as plants take in carbon dioxide and give off oxygen during photosynthesis, and animals take in oxygen and give off carbon dioxide during respiration. |
| decomposition | the decay of living things after they die. |
| nitrogen cycle | the repeated movement of nitrogen gas from the atmosphere into nitrogen compounds in the soil through living things. |
| evaporation | the changing of liquid to gas at the surface of a liquid. |
| water cycle | repeated movement of the water between the earth's surface and the atmosphere through evaporation, condensation, and precipitation. |
| condensation | changing a gas to a liquid. |
| respiration | process by which living things combine oxygen with food to produce energy. |
| precipitation | water that falls to the earth from the atmosphere. |
| combustion | chemical process involving oxygen that produces light and heat. |
| deforestation | the loss or reduction of forests due to natural causes and the destructive activities of people. |
| photosynthesis | process by which plants use light from the sun to make food. |
| resources | material from the earth that is used by living things. |
