Yet you could feel this grinding plate underneath us.

然而你能感觉到我们脚下的磨盘。

Our very distant relatives were bathed in calcium from those grinding tectonic plates, and so they used this to build the earliest bone-like tissues.

我们的远亲沐浴在那些研磨构造板块的钙中，所以他们用钙来构建最早的类骨组织。