Problem: Please answer a question about the following article about Pitch (music):
Pitch is an auditory sensation in which a listener assigns musical tones to relative positions on a musical scale based primarily on their perception of the frequency of vibration. Pitch is closely related to frequency, but the two are not equivalent. Frequency is an objective, scientific attribute that can be measured. Pitch is each person's subjective perception of a sound, which cannot be directly measured. However, this does not necessarily mean that most people won't agree on which notes are higher and lower.
Each persons perception of sound is called?
A: Pitch
Problem: Please answer a question about the following article about Insect:
The higher-level phylogeny of the arthropods continues to be a matter of debate and research. In 2008, researchers at Tufts University uncovered what they believe is the world's oldest known full-body impression of a primitive flying insect, a 300 million-year-old specimen from the Carboniferous period. The oldest definitive insect fossil is the Devonian Rhyniognatha hirsti, from the 396-million-year-old Rhynie chert. It may have superficially resembled a modern-day silverfish insect. This species already possessed dicondylic mandibles (two articulations in the mandible), a feature associated with winged insects, suggesting that wings may already have evolved at this time. Thus, the first insects probably appeared earlier, in the Silurian period.
The higher-level phylogeny is of the what?
A: arthropods
Problem: Please answer a question about the following article about FC Barcelona:
Barcelona won the treble in the 2014–2015 season, winning La Liga, Copa del Rey and UEFA Champions League titles, and became the first European team to have won the treble twice. On 17 May, the club clinched their 23rd La Liga title after defeating Atlético Madrid. This was Barcelona's seventh La Liga title in the last ten years. On 30 May, the club defeated Athletic Bilbao in the Copa del Rey final at Camp Nou. On 6 June, Barcelona won the UEFA Champions League final with a 3–1 win against Juventus, which completed the treble, the club's second in 6 years. Barcelona's attacking trio of Messi, Suárez and Neymar, dubbed MSN, scored 122 goals in all competitions, the most in a season for an attacking trio in Spanish football history.
What team did Barcelona defeat to win their 23rd La Liga title?
A: Atlético Madrid
Problem: Please answer a question about the following article about Dissolution of the Soviet Union:
On January 13, 1991, Soviet troops, along with the KGB Spetsnaz Alpha Group, stormed the Vilnius TV Tower in Lithuania to suppress the independence movement. Fourteen unarmed civilians were killed and hundreds more injured. On the night of July 31, 1991, Russian OMON from Riga, the Soviet military headquarters in the Baltics, assaulted the Lithuanian border post in Medininkai and killed seven Lithuanian servicemen. This event further weakened the Soviet Union's position internationally and domestically, and stiffened Lithuanian resistance.
What was attacked by Russians on July 31?
A:
Lithuanian border post in Medininkai