Question

question 4
1 pts
what observational evidence supports the fact that our universe is expanding?
discovery of black holes
redshifts of galaxies
detection of cosmic strings
discovery of quasars
evolution of galaxies with distance

Explanation:

Redshifts of galaxies show that most galaxies are moving away from us (Doppler effect for light: longer wavelengths indicate receding objects). Edwin Hubble observed that distant galaxies have greater redshifts, meaning they recede faster—key evidence for cosmic expansion. Other options (black holes, cosmic strings, quasars, galaxy evolution) do not directly support expansion.

Answer:

Redshifts of Galaxies