Which of the following features of the Martian surface are considered evidence of plate tectonics?
a. Volcanos
b. Valles Marineris
c. Presence of atmospheric gases common from volcanic outgassing.
d. Variations of terrain between the northern and southern hemispheres.
e. Lava flows may be responsible for filling in the craters, but the eruptions are not a result of tectonics.
f. None of the above - there is no evidence for tectonics.