Decide whether the following is an argument or explanation, given its context. Write "Argument" or "Explanation" in the first box. If the passage is an argument, write down its conclusion in the second box; if it is an explanation, write down the fact that is being explained in the second box. Because different wavelengths of light travel at different velocities when they pass through water droplets, they are refracted at different angles. Because these different wavelengths correspond to different colors, we see the colors separated. Therefore, if the conditions are right, rainbows appear when the sun shines through the rain. [Context: grade school science textbook]