What Is an Advantage of Quintessence Over the Cosmological Constant

Multiple Choice

What is an advantage of quintessence over the cosmological constant as a description of dark energy?

A) Einstein's reasoning in rejecting the cosmological constant still seems to be true today.
B) The cosmological constant would have to have, from the beginning of the universe, the right value to give a flat universe now: an amazing coincidence. The quintessence model does not have this requirement.
C) Quintessence is a well-established concept in physics, going back to ancient times, whereas the cosmological constant is a relatively new and untested concept.
D) The quintessence model predicts the correct age for the universe; the cosmological constant does not.