<Li> Sustainable and less polluting waste management including waste reduction (or even zero waste), reuse, recycling, composting, waste - to - energy, and anaerobic digestion of sewage sludge . </Li> <P> In some cultures the term environment is meaningless because there is no separation between people and what they view as the natural world, or their surroundings . Specifically in the United States, many native cultures do not recognize the "environment", or see themselves as environmentalists . </P>

How many types of natural resources exist on the earth