The correct answer is: "the scientific method".
Galileo Galilei (1564 - 1642) was an Italian astronomer, physicist and engineer, known as the "father of observational astronomy" and "of the scientific method".
He conducted research on speed and velocity, gravity and free fall, the principle of relativity, etc. Through observational methods, he was able to describe the properties of such phenomena and to develop "laws" as a starting point for human understanding of them. He confronted the Roman Inquisition by defending the heliocentrism theory developed by Copernicus.
The battle of Tours united Christians against Islamic expansion and this among the following events allowed Christianity to act as a unifying force in Medieval Europe. The correct option among all the options given in the question is the last option or option "d".
The Supreme Court held that the Supremacy Clause (Article VI, Clause 2), which elevates federal law above state law when the two are in conflict (and do notinvolve a right explicitly reserved to the states) protected the bank from being taxed by the State(s). Chief Justice John Marshall declared the states couldn'ttax the federal government. Case Citation:McCulloch v. Maryland, 17 US 316 <span>(1819) </span>
