题目

阅读理解Camels are large animals living in dry areas. There are two species of camels; the Arabian camel with a single hump(驼背) from the dry desert areas of West Asia, and the Bactrian camel with two humps from Central and East Asia. Camels are over 7 feet tall and weigh over 1,600 pounds. They will live up to 40 to 50 years. Most camels are domesticated(驯化) and fed by people. Camels are plant-eaters．Camels are very strong animals with wide, padded feet. They have thick leathery pads on their knees and chest. Camels have nostrils(鼻孔)that can open and close, protecting them fr物体静止放在水平桌面上, 则（ ）A．物体对桌面的压力与物体受到的重力是同一个力，性质相同B．桌面对物体的支持力与物体对桌面的压力是一对作用力与反作用力C．桌面对物体的支持力与物体受到的重力是一对平衡力D．物体对桌面的压力是桌面发生形变产生的