A sustainable energy source has which characteristic?

The LARGEST segment of renewable energy is:

The earliest renewable energy source used by humans was:

_____ consists of digging tunnels or shafts into Earth to reach buried ore deposits.

Even the most isolated regions on Earth are vulnerable to the effects of air pollution because atmospheric and hydrologic circulation moves chemical and particulate pollutants around the globe. This is an example of:

What is emitted during radioactive decay?

Which of the following represents the downside of using large dams for hydropower?

Which example is a waste that can be used to produce biofuel?

Which electricity energy source is LEAST expensive for most consumers?

The mass number for an element is composed of: