Life on Earth began about 3.5 billion years ago. The first life appeared in the sea. It was born into a world that looked very different from today. The atmosphere was filled with poisonous gases. The sky was pink, and the sea was rusty-red.
Is it true?
Earth is the only planet with life on it.
MAYBE. This is one of the greatest unsolved mysteries. Life probably does exist on other planets besides Earth, but nothing has been found so far. The search continues.
