PART A: Read the sentence from paragraph 2: “Churning currents in the molten rocks below propel them along like a jumble of conveyor belts in disrepair.” How does this sentence contribute to the reader’s understanding of the topic of the article? A by describing the geologic features that can form along each of the three types of tectonic boundaries B by providing an analogy connecting the concept of moving tectonic plates to a concrete image C by signaling a shift in the structure of the article to a chronological narrative D by connecting the introduction of the article to the central idea that the lithosphere is unique to planet Earth