Complex sentence: In contrast, there is no such path in the r-process, and while the s-process effectively stops at lead and bismuth, the r-process can go on to create even heavier elements such as thorium and uranium.
Split into simpler sentences: In contrast, there is no such path in the r-process. While the s-process effectively stops at lead and bismuth, the r-process can go on to create even heavier elements such as thorium and uranium.