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<dl>
<dt>Mercury</dt>
<dd>Mercury (0.4 AU from the Sun) is the closest planet to the Sun and the smallest planet.</dd>
<dt>Venus</dt>
<dd>Venus (0.7 AU) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core.</dd>
<dt>Earth</dt>
<dd>Earth (1 AU) is the largest and densest of the inner planets, the only one known to have current geological activity.</dd>
</dl>