human impacts

3. Renewable energy sources made from biological material such as plants or animal waste.
5. The increase in Earth’s average surface temperature caused by rising greenhouse gas levels.
7. The science and practice of cultivating land, growing crops, and raising animals.
8. The process by which green plants make glucose using sunlight, water, and carbon dioxide.
10. A method of clearing forest by cutting and burning vegetation for agriculture.
11. When heat energy absorbed by Earth’s surface is emitted back as infrared radiation.
13. The large-scale removal of trees, often to clear land for farming or building.
14. The variety of living organisms in a particular habitat or on Earth as a whole.
16. A site where waste material is buried under layers of earth.

1. A poisonous substance produced naturally by living organisms.
2. The build-up of toxic substances in organisms as they move up the food chain.
4. The breakdown of dead organisms into simpler substances by bacteria and fungi.
6. The process where excess nutrients in water cause algal blooms and oxygen depletion.
8. A type of partially decayed plant material found in bogs; releases carbon dioxide when burned.
9. Rain that contains dissolved acids from air pollutants like sulfur dioxide and nitrogen oxides.
12. A chemical or natural substance added to soil to increase plant growth. Contains nitrogen.
15. A type of air pollution formed when smoke and fog combine, often due to vehicle emissions.