CLEP Western Civ II

Answer: B - One of the most significant scientific advances at the turn of the 20th century was that the structure of atoms is changeable. Previously, scientists had thought that atoms were solid, inflexible objects. But through the work of scientists such as France's Pierre and Marie Curie and England's J. J. Thompson came a better understanding of the complex nature of atoms. This facilitated German physicist Max Planck's discovery that energy was far more fluid than had previously been thought. This era laid the groundwork for Albert Einstein's theory of relativity in the 20th century.