The Montreal Protocol limited the world’s use of chemicals like Chlorofluorocarbons (CFCs). Which sentence best indicates that the Montreal Protocol led to improvements in the thickness of the ozone layer? When ozone was first measured by satellite in 1979, the average concentration above Antarctica was 225 Dobson units (DU). In 1989, when the Montreal Protocol took effect, it was 127 DU. The lowest level was 92 DU in 1994.By 2019, the value was back up to 167 DU. Excerpt courtesy of NASA

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.