We can even understand it on a molecular or cellular level now.

如今我们已经能从,分子和细胞水平对机体进行研究

耶鲁公开课 - 生物医学工程探索课程节选

But variola, which causes smallpox in humans, and vaccinia, which causes a disease called cowpox in cattle, turned out to be, we now know, viruses that are molecularly very similar.

但是导致天花的人痘病毒,和导致牛痘,的牛痘病毒,后来发现其实是,我们现在知道,这两种病毒在分子水平上十分相似

耶鲁公开课 - 生物医学工程探索课程节选

By determining how many of those molecules to hold onto, how many to keep in the body, how many to release determines the internal composition with regard to that ion.

通过控制体内这些分子的水平,即体内保有多少,又排出多少,就能够保证内环境中离子组成的稳定

耶鲁公开课 - 生物医学工程探索课程节选