Which statement best distinguishes energy efficiency from renewable energy?

• A. Renewable energy reduces energy demand; energy efficiency supplies energy from replenish-able sources.
• B. Energy efficiency reduces energy demand; renewable energy supplies energy from sources that replenish naturally.
• C. Energy efficiency increases energy demand; renewable energy reduces supply.
• D. Renewable energy is only for electricity; energy efficiency only for heating.

Answer: (B)

The main idea is how energy efficiency and renewable energy address energy use in different ways: energy efficiency reduces the amount of energy needed to deliver a service, while renewable energy provides energy from sources that naturally replenish. Energy efficiency means using less energy for the same outcome—better insulation, efficient appliances, or smarter systems—so overall demand drops. Renewable energy refers to sources that replenish themselves, such as sun, wind, and biomass, supplying power rather than simply reducing it.

This makes the statement a good match: energy efficiency reduces energy demand; renewable energy supplies energy from sources that replenish naturally. The other options mix up these roles or impose limits that aren’t accurate—for example, efficiency doesn’t supply energy, and renewables aren’t confined to electricity or to heating alone.