How and why did columbus help to expand the spain empire

How does the pyramid of giza include art, science, math, or a need for infrastructure?

What were the short-term and long-term impacts of the american revolution

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