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 The
third planet from the sun is the Earth. About 4.6 billion years ago,
Earth was as hot as Venus. Then suddenly, 3.5 billion years ago, the
first life forms appeared. Earth is unique in many ways. It is the only
planet with drifting continents and islands. Also, water can exist in
the liquid form only on this planet, in our solar system.
Click on the buttons below to see more
on the inner planets.
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