II. Cases Description: 1. Name out one case to illustrate that the definition of the ‘environment’ assumes particular significance in relation to efforts to establish rules governing liability for damage to the environment. 2. During the first period of the development of the international environmental law, two environmental disputes were submitted to international arbitration. One is the Pacific Fur Seal Arbitration. Another is the Trail Smelter case. Please give more introduction about these two cases.