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Lesson 1 Assignment Unit I 1. In addition to various bits of information, there are 3 primary principles geologists use to place layers of rock according to age. The first, Principle of Superposition is the un-changed consecution of the rock, which contains the oldest stratum (a single sedimentary rock) located in the bottom of the rock. Superposition is the primary method to unveil the order of succession in which layers were formed in the rock. The second, Principle …

…to the free-floating huge iron ball, measuring 1,500 miles across. 20. When liquids and gasses of extreme high temperature travel to a cooler location, they will begin to transform and take the form of a solid-state. Scientists believe the convective motions of the asthenosphere inside the mantle cause the plates to shift on the Earth's surface. Unfortunately at present day, scientists can not be certain of the effect mantle convection have on the moving of tectonic plates.