"The study of history has value only to the extent that it is relevant to our daily lives."
"It is primarily through our identification with social groups that we define ourselves."
The following is a letter to the editor of an environmental magazine.
"The decli南昌癫痫病治疗医院哪家好ne in the numbers of amphibians worldwide clearly indicates the global pollution of water and air. Two studies of amphibians in Yosemite National Park in California confirm my conclusion. In 1915 there were seven species of amphibians in the park, and there were abu女性癫痫病的常规治疗方法ndant numbers of each species. However, in 1992 there were only four species of amphibians observed in the park, and the numbers of each species were drastically reduced. The decline in Yosemite has been blamed on the introduction of trout into the park's waters, wh癫痫这种病在发作的时候有规律吗？ich began in 1920 (trout are known to eat amphibian eggs). But the introduction of trout cannot be the real reason for the Yosemite decline because it does not explain the worldwide decline."