Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
<span>B. Rocks go through many stages during their formation</span><span>
Sedimentary rocks together with the igneous rocks and the metamorphic rocks are the three main types of rocks that existed on earth. It is formed or made accordingly into four major ways. First, it is formed by depositing weathered remains of "clastic sedimentary rocks" or other rocks. Second, is through accumulation and the consolidation of sediments, thirdly is by depositing the results of biogenic activity and lastly it is formed through precipitation from solution. Limestone, shale, chalk clay and others are best examples of sedimentary rocks. </span>
<span>a. an element is a substance that cannot be broken down</span>