Surface is relatively smooth. The northen hemisphere is largely rolling plain, the southern hemisphere cratered uplands. Much of planet is covered by red dust. Rocky planet, with an iron core.
Surface is no longer active.
Mostly carbon dioxide, with traces of nitrogen and other gases. When viewed from Earth, Mars looks red. This is due to covering of red dust containing iron oxide. Mars show variations in surface colouring. Originally taken to be sign of vegetation, it is now known to result in giant dust storms which leave darker laval material exposed.