Era 4

2. the process of forced or voluntary consolidation of individual peasant farms or private businesses into large, state-owned, or cooperative collective farms
4. A combination of science and agriculture to mass produce food with increased population sizes. (2 words)
5. the rapid increase, reproduction
8. Energy formed by wind (2 words)
10. The mating of animals or plants from different breeds
12. a weapon of mass destruction (2 words)
15. synthetic or mined inorganic compounds designed to supply essential nutrients (2 words)
19. The long-term, human-caused rise in the Earth's average surface temperature (2 words)

1. An increase of citizens in a certain area (2 words)
3. clearing of forests and standing trees, usually driven by human activity
4. Gases released into the atmosphere (2 words)
6. The act of attacking a target using incendiary devices designed to start large fires rather than relying solely on explosive blast destruction
7. Energy formed by sunlight (2 words)
9. The degradation of dry land ecosystems
11. A substance intended for preventing pests on plant.
13. a sudden, drastic rise in oil prices often accompanied by supply shortages (2 words)
14. a low-carbon energy source generated by splitting atoms—a process called fission—inside a nuclear reactor to create heat (2 words)
16. A form of land combat where opposing sides fight from, defend, and live in deep, dug-out, and fortified ditches in WWI (2 words)
17. Land that ins't good for planting crops on (2 words)
18. Brutal temperatures faced by Russians in WWII (2 words)