instruction:
This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
question:
Passage: Reflections generally affect polarization. For radio waves, one important reflector is the ionosphere which can change the wave's polarization. Thus for signals received following reflection by the ionosphere (a skywave), a consistent polarization cannot be expected. For line-of-sight communications or ground wave propagation, horizontally or vertically polarized transmissions generally remain in about the same polarization state at the receiving location. Matching the receiving antenna's polarization to that of the transmitter can make a very substantial difference in received signal strength. Question: What reflector can change the waves polarization?
answer:
ionosphere


question:
Passage: The army is led by a civilian Secretary of the Army, who has the statutory authority to conduct all the affairs of the army under the authority, direction and control of the Secretary of Defense. The Chief of Staff of the Army, who is the highest-ranked military officer in the army, serves as the principal military adviser and executive agent for the Secretary of the Army, i.e., its service chief; and as a member of the Joint Chiefs of Staff, a body composed of the service chiefs from each of the four military services belonging to the Department of Defense who advise the President of the United States, the Secretary of Defense, and the National Security Council on operational military matters, under the guidance of the Chairman and Vice Chairman of the Joint Chiefs of Staff. In 1986, the Goldwater–Nichols Act mandated that operational control of the services follows a chain of command from the President to the Secretary of Defense directly to the unified combatant commanders, who have control of all armed forces units in their geographic or function area of responsibility. Thus, the secretaries of the military departments (and their respective service chiefs underneath them) only have the responsibility to organize, train and equip their service components. The army provides trained forces to the combatant commanders for use as directed by the Secretary of Defense. Question: Who does the Chief of Staff serve as the principal military adviser to?
answer:
Secretary of the Army


question:
Passage: 
 India: Due to concerns about pro-Tibet protests, the relay through New Delhi on April 17 was cut to just 2.3 km (less than 1.5 miles), which was shared amongst 70 runners. It concluded at the India Gate. The event was peaceful due to the public not being allowed at the relay. A total of five intended torchbearers -Kiran Bedi, Soha Ali Khan, Sachin Tendulkar, Bhaichung Bhutia and Sunil Gavaskar- withdrew from the event, citing "personal reasons", or, in Bhutia's case, explicitly wishing to "stand by the people of Tibet and their struggle" and protest against the PRC "crackdown" in Tibet. Indian national football captain, Baichung Bhutia refused to take part in the Indian leg of the torch relay, citing concerns over Tibet. Bhutia, who is Sikkimese, is the first athlete to refuse to run with the torch. Indian film star Aamir Khan states on his personal blog that the "Olympic Games do not belong to China" and confirms taking part in the torch relay "with a prayer in his heart for the people of Tibet, and ... for all people across the world who are victims of human rights violations". Rahul Gandhi, son of the Congress President Sonia Gandhi and scion of the Nehru-Gandhi family, also refused to carry the torch. Question: How many bearers decided not to participate?
answer:

five