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 irrigation of crops more difficult.
D) eliminate farmland and wildlife habitats and often villages in the regions that are flooded.
Question 2
On Earth today, mountains such as the Himalayas are rising because of
A) extensive erosion caused by increases in rainfall in those regions.
B) subterranean pockets of natural gas forcing their way to the surface.
C) low density rocks that are being forced upward through high density rocks.
D) collisions between tectonic plates.
The greenhouse effect: heat trapping by earth's atmosphere.
The Greenhouse Effect
Variable Gases of the Atmosphere
Variable Gases: Carbon Dioxide
Hydroelectric power: 2013 Global Market
Greenhouse Effect