Mars Has a Crust That Is Everywhere Thicker Than Earth's

Multiple Choice

Mars has a crust that is everywhere thicker than Earth's crust.What is the primary reason for this?

A) Mars,being smaller,cooled more rapidly.
B) Mars is cooler because it is farther from the Sun.
C) Mars rotates too slowly to allow the crust to remain fluid.
D) Mars rotates too rapidly to allow the crust to remain fluid.