A science museum display describes a theory about how the universe began. A visitor says, "The theory is only a guess, because nobody observed the beginning of the universe."
Which reply to the visitor is correct?
It is an explanation that is supported by evidence and can be tested.
It is a description of what was seen at the beginning of the universe.
It is a fact, so it no longer needs to be tested against evidence.
It is accepted because it was suggested by famous scientists.
79 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.