According to recent research, during the final days of planet formation but before planets had fully formed, planetesimals, which were itinerant objects as large as Pluto, may have collided with Earth, Mars, and the moon. It is hypothesized that they deposited siderophiles (elements such as gold, platinum, and palladium) into Earth's crust. Siderophiles are typically drawn to iron, which forms much of the inner core of Earth. Logically, during planet formation, most of these elements would have been drawn into the center of Earth; however, their abundance in Earth's crust has long perplexed scientists. These collisions may also have caused Earth's axis to tilt by 10 degrees and deposited water on the moon.

Based on the information in the passage, which of the following best describes planetesimals?

(A) Free-roaming proto-planets
(B) Planets that collided with Earth and bounced out of the galaxy
(C) Objects embedded in Earth's crust
(D) Highly magnetic bodies that helped form planets
(E) Large rocks composed of siderophiles