Final answer:
Einstein expanded upon the ideas of Newton, Maxwell, and Planck in physics.
Step-by-step explanation:
The ideas that Einstein expanded upon belong to several different areas of physics. In terms of relativity, Einstein expanded upon the work of physicists such as Isaac Newton and James Clerk Maxwell. He developed the theory of special relativity, which introduced concepts like time dilation and the equivalence of mass and energy.
In terms of the nature of light, Einstein expanded upon the work of Max Planck and others to propose that light consists of particles called photons. These are just a few examples of the ideas Einstein built upon in his groundbreaking work.