Because the axis of Mars is tilted with respect to its orbit plane, the Martian atmosphere undergoes seasonal changes analogous to those on Earth.
(the axis of Mars; is tilted; with respect to its orbit plane) (the Martian atmosphere; undergoes; seasonal changes analogous to those on Earth)
the axis of Mars the Martian atmosphere
is tilted undergoes
with respect to its orbit plane
seasonal changes analogous to those on Earth