How did the iron oxide (rust) get on the planet Mars

I want to know how rust gets on Mars. I don't need really long answers or anything, I just want an answer.

The same way the earth and asteroids got their iron oxide, it came with the package during creation of the solar system.

Both Oxygen and Iron are two of the most common elements in the universe. Oxygen is the third most common element in the universe. Iron is the sixth most common. Hence it was rather inevitable that Mars, like Earth would end up with a plentiful supply of each.
http://en.wikipedia.org/wiki/Iron
http://en.wikipedia.org/wiki/Oxygen
http://en.wikipedia.org/wiki/Abundance_o…

The Earth also has vast deposits of iron oxide. It is just that on Earth those deposits are covered by thick layers of sediment that were layed by the actions of weathering.
http://en.wikipedia.org/wiki/Banded_iron…
http://en.wikipedia.org/wiki/Weathering

There's iron in the rocks, and the oxygen comes from the thin layer of frost that collects at night. in the morning, most of it sublimates away, but some of it is split into oxygen and hydrogen by the sunlight. The oxygen combines when the iron and so you have rust. It is very thin, however, only on the surface of the rocks.

High natural iron contents, proven there is or was water, and it has a light atmosphere and at one time had a atmosphere all enlightened to cause oxidation

God