The correct option is "They agreed that natural resources needed to be conserved for the future."
National Park System, NPS is a federal system of protected areas in the United States that includes the collection of all units managed by the National Park Service. The system as a whole is considered a national treasure and sometimes, some of the most famous national parks and national monuments are metaphorically called the "crown jewels".
• a first stage of beginnings (1864-1916), which begins with the transfer of Yosemite to California for its preservation, in which natural areas and archaeological elements are protected individually, through the declaration of national parks (and since 1906 National monuments). This stage ends on August 25, 1916, when President Woodrow Wilson signed a law of Congress, the National Park Service Organic Act, authorizing the creation of the National Park Service. ("National Park Service").
• A second stage of establishment and growth (1916-33), which continues to increase the number of protected areas, which are increasingly diverse and ending on June 10, 1933 when President Franklin D. Roosevelt established a unique «National Park System», consolidating in it all the national parks and national monuments, the national military parks, the eleven national cemeteries, the national memorials and the National Capital Park.
