物体原子序数越大，X射线的穿透本领越　。（请填写大或者小）The larger the atomic number of the object, the the X-ray　penetration power.（Please fill in larger or smaller)

物体原子序数越大，X射线的穿透本领越　。（请填写大或者小）The larger the atomic number of the object, the the X-ray　penetration power.（Please fill in larger or smaller)
正确答案：小