How did these vast valleys on Mars form? (This is a shaded relief map; the colors represent elevation.)

This crater on the Moon is probably ________.  

Which of these four lunar impact craters is the youngest?

This is an image of part of the Moon’s maria. Which feature was produced by contraction?

Which is the correct sequence of planets, based on increasing distance from the Sun?

Study this thermal evolution diagram, which shows how the interior of a terrestrial planet should change with time and temperature. Select the part of the image that corresponds to the asthenosphere.

What are the ages of most meteorites that fall to Earth?

Select the letter on the following cross section of Earth that shows where the Silicic continental crust is made.

Study the following image of Vesta. What is the most likely cause of the linear ridges and grooves near the equator of Vesta?

Click on the possible explanations for Mercury’s large core. Choose the two most likely.