Which of these planets has polar ice caps?

The two polar regions of the planet Mars feature extensive plains:

“Planum Boreum” ("the northern plain") extends northward from roughly 80°N.

“Planum Australe” ("the southern plain" extends southward of roughly 75°S. The geology of this region was to be explored by the failed NASA mission Mars Polar Lander, which lost contact on entry into the Martian atmosphere.

Like Earth, the planet Mars has polar ice caps: they are located within these two plains and consist of primarily water-ice with a few percent dust. Frozen carbon dioxide makes up a small permanent portion of the “Planum Australe”. In both Martian hemispheres a seasonal carbon dioxide frost deposits in the winter and sublimates during the spring.

Data collected in 2001 from NASA missions to Mars show that the southern residual ice cap undergoes sublimation inter-annually. The most widely accepted explanation is that fluctuations in the planet's orbit are causing the changes.