Ineed answering question 29 and 30

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Ascientist performs an experiment where she measures the mass of a piece of metal, pours acid onto the metal, washes the metal, and then re-measures the mass of the metal. the scientist repeats the experiment several times, each time increasing the amount of acid used. the dependent variable in the experiment is the: initial mass of the metal final mass of the metal amount of acid used washing the metal

One of galileo’s contributions to science was a creating the coordinate plane system. b developing the scientific method. c improving the telescope. d inventing the astrolabe.