Mars has seasons, just as Earth does. Its axis is tilted roughly the same angle as another planet, _______________________. Because Mars is further from the Sun, the length of each season is about _______________________. Mars has two polar caps, with ice made of frozen water and ________________________. The red planet has the huge Mariner Valley canyon system extending nearly a quarter of the way around the planet. This system was formed by __________________ of the
crust and has been widened by _______________________