The inner planets are the closest planets to the sun. They are mostly made up of rocks and metals. They are divided from the outer planets by a asteroid belt
They are have the most density compared to the outer planets and have the most circular orbit. They also have less gasses than the outer planets. They also have atmospheres while the outer planets have rings.
The reason why Earth can sustain life is that it has an atmosphere, water, and the temperature is livable (not too hot and not too cold)
What I found most interesting is that only Earth can sustain life. The only planet that is livable.
