Yes, you are correct about change of water into water vapours , also you will think it is doesn't have any importance and is waste for the plant energy. But it is a “NECESSARY EVIL” as it cools down the plant , transport water,minerals and also Plant hormones,etc. May you got your answer
Jackson wanted to abolish it, the bankers were just giving there money (loans) away & those people would buy land somewhere else for cheap & wait for settlers too pay to live there , as a result of this, Jackson made it harder to get money from the banks
I believe it's quadratic, as quadratic matches the second time while linear matches the first time you find the differences.