Earth, our home planet, is the third planet from the sun. it is the fifth largest planet in our solar system. it is the only planet we know of where life exists. earth has hundreds of names in many languages. it has one moon.

in some ways, earth is similar to mercury, venus and mars. they are all hard, rocky planets. all four have meteor impact craters. like mars and venus, earth has volcanoes, mountains and valleys.

but earth is different in very important ways. most of our planet is covered with water. the air is made of nitrogen, oxygen and a little carbon dioxide, which makes it just right for us to breathe. earth is home to people, plants and animals because it has both water and the right kind of atmosphere.

earth's moon is the brightest and most familiar object in the night sky. in many ways, the moon is responsible for making earth such a great home. it stabilizes our planet's wobble. since the moon stabilizes earth's wobble the weather is nicer.

which is the best summary statement for this passage?
a) like mars and venus, earth has volcanoes, mountains and valleys.
b) earth's moon is the brightest and most familiar object in the night sky.
c) in some ways, earth is similar to other rocky planets.
d) earth is quite similar to other planets, but different in that it alone supports life.