Although Hydroelectric Dams Generate Electricity Without Producing Greenhouse Gases,they

Although hydroelectric dams generate electricity without producing greenhouse gases,they

A) are short-lived structures that have to be rebuilt about every 20 years.
B) are only able to contribute to about 5% of the electrical power throughout the world.
C) alter water control in ways that make it more difficult to irrigate crops.
D) eliminate farmland and wildlife habitats and often villages in the regions that are flooded.