One consequence of einstein's theory of special relativity is that mass is a form of energy. this mass-energy relationship is perhaps the most famous of all physics equations:
e=mc2,
where m is mass, c is the speed of the light, and e is the energy. in si units, the units of speed are m/s. for the preceding equation to have consistent units (the same units on both sides of the equation), the units of e must be which of the following?