apical axis

例句：

1. 1. The axis of the planet revolves around its center.
   行星的轴心围绕其中心旋转。
2. 2. The axis of the Earth's rotation is located at the North Pole.
   地球自转的轴心位于北极。
3. 3. The axis of symmetry divides the object into two equal halves.
   对称轴将物体分成两个相等的部分。