如图是三种脊椎动物形态结构示意图，请据图回答：
把3米长的绳子平均分成5份，1份是 15 米．
不等式组y≥0y≥x-2y≤x所围成的封闭图形的面积为（ ）
—This apple pie is too sweet, don't you think so?
—_____. I think it's just right, actually.
