Final answer:
It is necessary to correct the readings of the respirometers containing seeds because the seeds respire through cellular respiration and produce carbon dioxide.
Step-by-step explanation:
It is necessary to correct the readings of the respirometers containing seeds because seeds respire through cellular respiration, which produces carbon dioxide. This carbon dioxide can accumulate in the respirometer and affect the readings, making them inaccurate. By measuring the transmission of light through a control tube with only broth in it, we can account for any optical properties of the broth and subtract those readings from the readings of the respirometer with seeds, giving us a more accurate measurement of the carbon dioxide produced by the seeds.