读句子，写出正确的国家名。

1. It's north of the U. S.. It has Niagara Falls.  __________________

2. It's west of China. It has a king or a queen.  __________________

3. It's east of China. It has Statue of Liberty.  __________________

4. It's flag is red, and it has five yellow stars.  __________________

自然界存在没有细胞的生命。