Short Answer
Baryonic matter, cold dark matter, and a cosmological constant (dark energy) is the best answer.
Astrophysics questions often combine observation with first-principles physics. The winning move is to connect the measurement being made, such as luminosity, spectrum, redshift, or orbit, to the physical model behind it.
ΛCDM (Lambda-Cold Dark Matter) is the standard cosmological model with baryons, CDM, and a cosmological constant Λ.
Why This Answer Is Correct
This is a Hard-level question in Astrophysics & Cosmology. The prompt is really testing whether you can connect the concept to its defining physical relationship instead of picking a nearby-but-wrong term.
Good astrophysics reasoning always asks what the telescope actually measured and what physical quantity that measurement traces.
Choices At A Glance
- A. Only baryonic matter and radiation
- B. Baryonic matter, cold dark matter, and a cosmological constant (dark energy)
- C. Warm dark matter and inflation only
- D. No dark energy
When similar options appear on an exam, eliminate the ones that break the core law, use the wrong units, or confuse a definition with a consequence.
Topic Snapshot
Topic: Astrophysics & Cosmology
Difficulty: Hard
Best next move: Re-state the governing law in your own words, then solve one more example from the same topic before moving on.