A student is writing from the following notes about color-changing chemical sensors: - A chemical sensor strip turns purple when lead is present in water. - The strip does not require electricity or laboratory equipment. - Community volunteers can carry the strips during field surveys. - Samples that turn purple are sent to a laboratory for confirmation. The student wants a sentence that links the first idea, the sensor's visible color change, with the next idea, its use in field testing. Which choice is most effective?