How do the Egyptians live?

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

Which of the following was probably the most difficult challenge facing construction of the railroad?

Who were the only people that were not allowed to be a citizen in the roman empire