Homework Help: science

Posted by Briana on Monday, December 1, 2008 at 7:48pm.

I have a picture that shows what scientists think parts of North America looked like 300 million yrs ago. ie, trees, plants , insects, rocks. How do scientists know what North America looked like so long ago, if there were no people around to see it?

science - Count Iblis, Monday, December 1, 2008 at 8:00pm
Fossils. By studying fossils and also the geological record one can reconstruct how the Earth looked like.

See also this program about the first trees:

http://www.bbc.co.uk/worldservice/specials/948_discovery_2008/page3.shtml
science - DrBob222, Monday, December 1, 2008 at 8:01pm
Geologists, paleontologists, hydrologists, and others, study the landscape, the continental plates, fossils, etc and draw conclusions from those studies about various time frames.
science - drwls, Monday, December 1, 2008 at 8:01pm
Fossils and radioactive dating techniques. It is possible to assign an age to layers of earth at different depths.
science - sasha, Tuesday, December 2, 2008 at 7:25pm
how do we grow quickly do we grow

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