Take the example of biodegradable Natureworks PLA plastic http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm Polylactic Acid or PLA "plastic" http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm その他の課題 http://environment.about.com/od/greenlivingdesign/a/pla.htm tradeoffs http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm http://environment.about.com/od/greenlivingdesign/a/pla.htm Pros And Cons Of The Corn-Based Plastic PLA http://environment.about.com/od/greenlivingdesign/a/pla.htm more http://environment.about.com/od/greenlivingdesign/a/pla.htm unsolved problems http://environment.about.com/od/greenlivingdesign/a/pla.htm