1. Why Are Resources Reusable?
Chapter 14 Key Issue 3
Why Are Resources Reusable?

2. Renewing Resources
The leading renewable resources are biomass and hydroelectric power.
Geothermal and wind power are also becoming important.
Wood and plants are important forms of biomass that are renewable resources if they are carefully harvested.
The energy of moving water has been used to generate hydroelectric power, which is the second most important source of electricity after coal.
The biggest drawback with hydroelectric power is that it is often generated by the building of dams that can cause serious environmental damage.
Geothermal energy is generated from hot water or steam in volcanic areas, especially Iceland.

3. Solar Energy
Solar energy is potentially the most important renewable resource. It can be harnessed either through passive or active means.
Passive solar energy systems capture solar energy without any special devices, whereas active solar energy systems collect solar energy and convert it to heat energy or electricity.

4. Recycling Resources
Recycling is the separation, collection, processing, and reuse of unwanted material.
Recycling has increased in the United States since 1970.
Recycled products are picked up, processed, and manufactured into marketable products.