The answer is B<em><u>One cause (star material gathers) leads to one effect (inward pressure grows), which becomes a cause of two additional effects (nuclei zip and zoom, and nuclei veer away from each other).</u></em>
One cause (star material gathers) leads to one effect (inward pressure grows), which becomes a cause of two additional effects (nuclei zip and zoom, and nuclei veer away from each other).