Respuesta :

Alternate energy: energy that is not popularly used and is usually environmentally sound, such as solar or wind energy(as opposed to fossil fuels). 

SO... Biofuels are the only one that is not environmentally sound. Natural gas is no greenhouse gas and is safe for the environment. Solar power is power from the sun. Hydroelectricity is the power that comes from moving water AKA dams.

The correct answer is B) natural gas.

All of the following are examples of alternative energy sources except natural gas.

Biofuels, natural gas, solar power, and hydroelectricity are examples of alternative energy sources.

Natural gas is fossil fuel, not an altenative energy sources. There is plenty of natural gas reserves in the United States- Indeed it is exported to other countries such as Mexico.

Biofuels are produced by biomass, that is matter derived from animals and plants. Is a good source of alternative energy with solar energy and hydroelectricity, that help to take care of the environment.