indicated above are picture that how tree play a vital role in water and oil conervation. in the left hand picture, people are fleeing from voraciou and dune becaue they cut down all the tree. the caption read, "a the and advance, we retreat." in the right hand picture, the people have returned carrying tool, water and ampling for the reforetation of the land. we are informed that, "a we advance, the and retreat."it eem that the cartoonit i ending a meage about the ignificance of tree in water and oil conervation and the need for everyone to fight againt the danger of the deertification. in fact, what he i aying i if we do not fight againt the and, it will drive u away from the land. if we let thi ituation go a it i, our environment will uffer a great detruction.
the bet way to fight back againt the greedy deert i made clear in the econd picture. there the local people are vigorouly etting about the tak of planting tree to reclaim the land and make it fertile. the fact that there are three people in the picture, each with a different job ugget that cooperative effort i one of the key to ucce in the battle againt oil eroion and only in thi way can deertification be finally defeated.