Four years later, on October 10, 1976, the Viking 2 spacecraft took this picture of the Martian north polar cap. (solarviews.com)
It appears that much at least of the surface of Mars has two seasons of vegetal growth, the one quickened by the north polar cap, the other by the south. (scientificamerican.com)
Unlike the south polar cap, the north polar cap probably consists of water - ice. (solarviews.com)