What is meant by "dark energy"?

Question

Quizplus · Accepted Answer

Dark energy refers to the unknown force responsible for the observed accelerating expansion of the universe. It is thought to make up about 68% of the total energy density of the universe.

Answer: A, D, E 
 None of these choices accurately describe dark energy as they refer to dark matter and the early universe. Dark matter, unlike dark energy, is thought to be composed of particles that interact only weakly with other matter, and its energy is not necessarily related to mass through E=mc². Additionally, dark matter particles are believed to be non-relativistic and cannot be highly energetic. Finally, dark energy was not present in the very early universe, but instead became dominant relatively recently.

What Is Meant by "Dark Energy