Read the excerpt from "Exploring Mars." Which word in the excerpt is most repeated, hinting that it's part of the central idea? The Mars rat was not real—it was just an illusion. People saw illusions on Mars long before rovers reached the Red Planet. When people looked at Mars, they seemed to expect it to be like Earth. O Mars rat O rovers O Earth Save and Exit Next Submit Mark this and return Go MIT O ch 63°F Mostly cloudy