2. How does the author develop the central idea over the course of the article?
a. By explaining what NASA learned from previous rover missions sent to Mars.
b. By outlining the steps Curiosity will follow in examining the surface of Mars.
c. By arguing that more money should be made available to fund future missions to Mars.
d. By describing the newer features of Curiosity and how they will benefit the Mars mission.
i NEED HELPP