Problem: Given the question: Extract the answer to the question from the following context. Question: What did Villa refer to the leader of the U.S. government as? Context: The situation became so tense that war with the United States seemed imminent. On April 22, 1914, on the initiative of Felix A. Sommerfeld and Sherburne Hopkins, Pancho Villa traveled to Juarez to calm fears along the border and asked President Wilson's emissary George Carothers to tell "Senor Wilson" that he had no problems with the American occupation of Veracruz. Carothers wrote to Secretary William Jennings Bryan: "As far as he was concerned we could keep Vera Cruz [sic] and hold it so tight that not even water could get in to Huerta and . . . he could not feel any resentment". Whether trying to please the U.S. government or through the diplomatic efforts of Sommerfeld and Carothers, or maybe as a result of both, Villa stepped out from under Carranza's stated foreign policy.
++++++++++++++++++++++++++++++++
The answer is:
Senor Wilson

Problem: Given the question: Extract the answer to the question from the following context. Question: The Persian Revolt led to which person taking over Media? Context: In 550 BC, Cyrus the Great, son of Mandane and Cambyses I, took over the Median Empire, and founded the Achaemenid Empire by unifying other city states. The conquest of Media was a result of what is called the Persian Revolt. The brouhaha was initially triggered by the actions of the Median ruler Astyages, and was quickly spread to other provinces, as they allied with the Persians. Later conquests under Cyrus and his successors expanded the empire to include Lydia, Babylon, Egypt, parts of the Balkans and Eastern Europe proper, as well as the lands to the west of the Indus and Oxus rivers.
++++++++++++++++++++++++++++++++
The answer is:
Cyrus the Great

Problem: Given the question: Extract the answer to the question from the following context. Question: What is used to achieve goals in living organisms? Context: Instead, he formulated the spearhead model of evolution, a version of genetic pluralism. According to this model, living organisms themselves have goals, and act according to these goals, each guided by a central control. In its most sophisticated form, this is the brain of humans, but controls also exist in much less sophisticated ways for species of lower complexity, such as the amoeba. This control organ plays a special role in evolutionit is the "spearhead of evolution". The goals bring the purpose into the world. Mutations in the genes that determine the structure of the control may then cause drastic changes in behaviour, preferences and goals, without having an impact on the organism's phenotype. Popper postulates that such purely behavioural changes are less likely to be lethal for the organism compared to drastic changes of the phenotype.
++++++++++++++++++++++++++++++++
The answer is:
control organ