题目内容：

阅读下列短文，根据短文内容填空，在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

According to the World Wildlife Fund, only about 3,890 tigers are left in the wild. India is home to 70 percent of them, and its role in 1. (ensure) the big cat’s survival can’t be understated. Tiger numbers in India are believed to have dropped from about 40,000 at the beginning of the 2.（19）century to just 1,800 in the early 1970s, when India launched the conservation program Project Tiger. Kanha was one of the original nine3. (reserve)  set up under that program.