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Item 1
Which of the following indicates that the universe is expanding?
The spectra of Cepheid variables, which are found only in our galaxy, are blue shifted.
The spectra of Cepheid variables, which are found only in our galaxy, are red shifted.
The spectra of Cepheid variables, which are found in all galaxies, are red shifted.
The spectra of Cepheid variables, which are found in all galaxies, are blue shifted.