By the turn of the 20th century, the country's once expensive forests had been reduced by as much as

A) 30 percent
B) 50 percent
C) 65 percent
D) 80 percent

Hetch Hetchy

A valley in Yosemite National Park, which was controversially dammed in the early 20th century to provide water to San Francisco.

Conservationists

Individuals or groups who advocate for the preservation and protection of the environment and wildlife.

Sierra Club

An environmental organization established in the United States, dedicated to the protection and preservation of the natural environment through advocacy and conservation efforts.