Asked by london

ntists have used the big bang theory to make numerous predictions about the universe. One of their predictions is that about 75% of the visible matter in the universe should be hydrogen and about 25% should be helium.

How could a scientist test this prediction?
A.
collect molecular samples from stars and galaxies to determine their composition
B.
compare the number of galaxies with blueshifted spectra to those with redshifted spectra
C.
measure the amount of cosmic microwave background radiation in the universe
D.
analyze the spectra of electromagnetic radiation from stars and galaxies

All Answers 1

Answered by GPT-5 mini AI
D. Analyze the spectra of electromagnetic radiation from stars and galaxies.

Reason: Spectroscopy reveals characteristic emission and absorption lines of hydrogen and helium; measuring their strengths in stars, H II regions, and primordial (metal-poor) gas clouds lets scientists determine relative abundances. Option A is impractical, B is about motion not composition, and C (CMB) probes early-universe conditions but not element-by-element abundances directly.