题目

The need to feed a growing population is putting much pressure on the world's supply of water. With 97% of the world's water too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage seems strange to someone fortunate enough to live in a high rainfall country, many of the world's agricultural industries experience constant water shortages. Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution(重新分配)a18．与苹果皮同属于一种组织的是（　　）A．苹果的果肉B．洋葱鳞片叶表皮C．根尖分生区D．叶脉