During a cosmological survey, the redshift z z\,z of several distant galaxies is plotted against their distance d d\,d from Earth.
Explain how the observation of redshift in these galaxies, and its relationship with distance, provides evidence for the expansion of the Universe.
53 exam-style questions on Edexcel GCSE Physics 7.2 The Universe and red-shift. Each one has a worked solution and a mark scheme showing where the marks go.