The author of the passage implies which of the following about 25,000 years ago? A. The coastline of the region that is now the United States is longer than it was 40,000 years ago. B. Rivers in what is now the United States were numerous than they are now. C. Australia was less densely populated at that time than was the region that is now the United States. D. Australia's climate was significantly drier than it is now. E. Global sea level was lower than it is now.