Final answer:
The question can't be sufficiently answered without the specific text from Ray Bradbury's story "April 2000: The Third Expedition" from The Martian Chronicles, as the explanation for the similarities between Mars and Earth given by the Martians in the story is not covered in real-world scientific literature about Mars.
Step-by-step explanation:
The question refers to a story from Ray Bradbury's The Martian Chronicles, specifically the chapter titled "April 2000: The Third Expedition." In this story, the crew of the third expedition to Mars is surprised by the Earth-like appearance of Mars and the human-like appearance of the Martians they encounter. The question asks how the Martians explain the similarities between Mars and Earth. Given the literature-based nature of the question and the fact that it involves analyzing a work of fiction, a correct response cannot be provided without having the specific text, as the details requested are not covered in the scientific literature about Mars. The question is rooted in the interpretation of a fictional work, and does not pertain to factual scientific observations or data about the real Mars.