Question 1[Maximum number: 1]The Hubble constant is 2.3×10−18 s−12.3 \times 10^{-18} \mathrm{~s}^{-1}2.3×10−18 s−1.Outline how observations of spectra from distant galaxies provide evidence that the universe is expanding.Show Answerall distant galaxies exhibit red-shiftOWTTEAdd to Test