How did the lunar maria form?
Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins.
Why does the Moon have a layer of powdery "soil" on its surface?
It's the result of gradual erosion by micrometeorites striking the Moon.
The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that
the Caloris Basin formed toward the end fo the solar system's period of heavy bombardment.
Why do we think Mercury has so many tremendous cliffs?
They were probably formed by tectonic stresses when the entire planet shrank as its core cooled.
Which of the following does not provide evidence that Mars once had flowing water?
The presence of vast canals discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell.
How have we been able to construct detailed maps of surface features on Venus?
by using radar from spacecraft that were sent to orbit Venus
Which two geological processes appear to have been most important in shaping the present surface of Venus?
volcanoes and tectonics
Why are there fewer large craters on the seafloor than on the continents?
The seafloor crust is younger than the continental crust.
How does seafloor crust differ crom continental crust?
Seafloor crust is thinner, younger and higher in density.
Why is continental crust lower in density than seafloor crust?
Continental crust is made from remelted seafloor crust and therefore only the lower-density material rises to form it.