What is the primary reason most distant galaxies exhibit a cosmological redshift?

Answer

The expansion of the fabric of spacetime stretches the light as it travels across the void.

The overall expansion of the universe causes the fabric of spacetime to stretch, lengthening the wavelength of light emitted from distant receding galaxies, leading to a cosmological redshift.

What is the primary reason most distant galaxies exhibit a cosmological redshift?
astronomyuniverseredshiftDoppler effectblue shift