Which gas was present in the early earth atmosphere?
What do scientists think was responsible for much of the gases in the early earth atmosphere?
Which gas makes up nearly 80% of our current atmosphere?
Granite is an example of which type of rock?
Which type of rock is it most likely to be if it contains fossils?
What type of crystals will an extrusive igneous rock have?
Which type of rock is formed from cooled magma?