What does the sand do in the fracking process?

Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change

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.

Acontrol during an experiment. might change remains constant does not exist does change