Based on fossil evidence, about how long ago did the first single-celled life form appear on Earth? 130 million years ago
1.5 billion years ago
2.5 billion years ago
4.1 billion years ago

How can health insurance increase life expectancy

When studying the calumet region of illinois and indiana alfred meyers noted four stages of development as new groups occupied this land in stage 2 farmers used the land primarily to grow food for their familes and their small communities

The point where two air masses meet is called a