<span>Mars is known as the "Red Planet" because of an abundance of iron oxide on its surface.</span>The high abundance of iron on the surface of mars is indicative of the fact that Mars never melted as extensively as Earth. <span>Mars' smaller size (and weaker gravity) allowed it to remain less differentiated. </span> <span>But, despite Mars's high surface iron content, its overall magnetic field is weak compared to that of Earth. </span>
Earthquakes and matching fossils from different continents, not sure about a third thing. Maybe go with mountains and ravines? They’re formed by the continental plates pushing against one another