13. The giant impact theory attributes the origin of the Moon to the impact of a Mars-size body with the Earth. Which of the following is both a true statement and supports the impact theory of the Moon's origin? A. The impacting body sank inward to form the Earth's core. B. The impact was the same event that caused the extinction of the dinosaurs. C. The composition of the Moon is similar to Earth's but somewhat different. D. The scar left by the impact can be identified with the Pacific Ocean