Mercury.
Venus.
Venus
Earth is an inner planet because it has an atmosphere. Earth Rocks!
murcury
Mercury is the only planet (and inner planet) without an atmosphere - due to its small size. Mars has an atmosphere, but it is a thin one, mainly of carbon dioxide.
Mars
EARTH!!!!!!!!
Negative, not only do the inner planets have atmospheres, but the outer planets also have atmospheres. The masses of the outer planets are great, enough easily to hold an atmosphere. In fact it's Mercury, an inner planet, that has almost no atmosphere. True, Mercury has a less mass and the closeness to the sun make it impossible to hold on a atmosphere. As matter in fact, Mars had a atmosphere, but the solar wind had almost eaten all the atmosphere that Mars had.
Earth is the only known planet with an oxygenated atmosphere.
Because it is the only planet that we know of having a atmosphere
Venus