Like the grains of sand on a beach, the chip is made mostly of silicon, next to oxygen the most abundant element on the surface of the earth.
句意：就像海滩上的沙粒一样，芯片主要由硅制成，是仅次于氧气的地球表面最丰富的元素。next to此处意为仅次于。only secondary to仅次于。B选项与划线处意义相符，故选B。