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Our FutureProgress or Disaster?
The Need for Ecological Balance
section two food
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agricultural air pollution animals areas average baby boom bacteria behavior biological breeds Calories carbon dioxide cause century changes Chapter chemical energy contraceptive costs couples crops cycle death rates decline decrease densities develop disease ecological economic growth ecosystem effects environment environmental estimates Europe eutrophication example factors family planning farmers fertilizer fewer children Figure fish food chain fuel gallons grain Green Revolution grow heat helium higher important improved income industrial insecticides Lake land large numbers Latin America less levels limit major material consumption ment metabolic million mineral molecules natural nitrogen nitrogen cycle nonindustrial countries nutrients organisms organophosphate oxygen percent pesticides pests phosphate phosphorus photosynthesis plants pollution poor population densities population growth population increase problems processes production profitable programs proposals protein rapid reactors recycling regions reproduction result sewage social soil Source supply tion United waste women