The existence of dark mass and dark energy is not yet understood.
What does this mean for the current model of the universe?
The model must be completely wrong and abandoned
The model is complete but too difficult to explain
The model is incomplete and may need to be changed
The model can no longer be tested by observation
41 exam-style questions on AQA GCSE Physics 8.2 Red-shift, covering 8.2 Red-shift. Each one has a worked solution and a mark scheme showing where the marks go.