A Key Difference Between the Protoplanets That Formed in the Outer

Multiple Choice

A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that

A) those in the inner solar system were much larger than those in the outer solar system
B) those in the outer solar system included far more metal and rock, and thus the outer planets could be denser
C) those in the outer solar system were in a place where ice, not just rock, condensed and thus could grow larger
D) those in the outer solar system did not have enough planetesimals nearby
E) you can't fool me, there were no differences between the inner and outer protoplanets; only the planets that finally formed are different.
Section 14.3: Comparison with Other Planetary Systems