<span>The first striking change occurs with the appearance of new weapons. A machine gun was designed that used the recoil to operate the mechanism of the weapon in a continuous manner. The Parabellum-Pistole (Pistol Parabellum), is a semiautomatic pistol operated by recoil. There were three types of general-purpose pistols: revolvers, automatic pistols, and semiautomatic pistols. The rifle, became the most crucial infantry weapon, of the battlefields. The gases made their appearance sowing horror in the trenches, and the tank was undoubtedly one of the great novelties of the Great War.</span>
<u>The correct answer is C. They were rejected by scientists, who believed farmers would always produce enough food. </u>Malthus's studies affirmed that the moment in which the land stopped producing enough food for all its inhabitants was inevitable. Over time it was proved that this theory was false since it did not consider important variables that would occur in the following decades, such as the implementation of birth control techniques and related technological advances applied to agriculture and food production .
The organization Al Qaeda led by Osama Bin Laden was the perpetrator of 9/11
