A student investigated transpirational water loss in two different cultivars of maize, Cultivar X and Cultivar Y, over a 6-hour period. The cumulative mass of water lost was recorded, and the results are shown in the graph below.
a.[2]
Calculate the difference in the cumulative mass of water lost by Cultivar X compared to Cultivar Y at 3 hours. Show your working.
b.[3]
Calculate the average rate of water loss for Cultivar X between 3 hours and 6 hours. Include the correct unit in your answer.