With the support of many early conservationists, scientists, and other advocates, Everglades National Park was established in 1947 to conserve the natural landscape and prevent further degradation of its land, plants, and animals.
D. exhausting a natural resource is not sustainable
The main mechanism through which the layering happened is gravity: it pulled the heavier, denser material to the center, leaving the less dense material on the surface.
The material that was on the outside cooled quicker, but this was the result, not the cause.
The answer is
<span>2) Gravity caused more-dense material to move toward the center of each planet.</span>
