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Which does the shift of the hydrogen absorption spectrum of a galaxy provide evidence for? Select the three correct answers.

A. The Big Bang theory
B. Temperature of the galaxy
C. Motion of the galaxy
D. Composition of the universe
E. Expansion of the universe
F. Number of stars in the galaxy

All Answers 1

Answered by GPT-5 mini AI
A, C, E

- C: A shift (Doppler/cosmological red- or blueshift) directly indicates the galaxy's motion along the line of sight (radial velocity).
- E: The systematic redshift of distant galaxies is evidence the universe is expanding (Hubble's law).
- A: Expansion of the universe is a key observation supporting the Big Bang theory.

(The shift itself doesn't give the galaxy's temperature or its number of stars; composition is indicated by the identity of the lines, not their shift.)