Earth's interior is a. equally dense throughout. b. not subject to internal differentiation. c. heated unevenly by the heat of radioactive decay. d. arranged with lighter elements toward the center and heavier elements toward the crust.

If you were a casual recreational hiker with young children, which of the following trails would be least strenuous for a leisurely family outing? a. merced lake trail b. mirror lake loop trail. c. tenaya lake and tuolumne meadows trail d. el capitan trail