Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In the 1960s, Downtown Houston consisted of a collection of mid-rise office structures. Downtown was on the threshold of an energy industryled boom in 1970. A succession of skyscrapers were built throughout the 1970smany by real estate developer Gerald D. Hinesculminating with Houston's tallest skyscraper, the 75-floor, 1,002-foot (305 m)-tall JPMorgan Chase Tower (formerly the Texas Commerce Tower), completed in 1982. It is the tallest structure in Texas, 15th tallest building in the United States, and the 85th tallest skyscraper in the world, based on highest architectural feature. In 1983, the 71-floor, 992-foot (302 m)-tall Wells Fargo Plaza (formerly Allied Bank Plaza) was completed, becoming the second-tallest building in Houston and Texas. Based on highest architectural feature, it is the 17th tallest in the United States and the 95th tallest in the world. In 2007, downtown Houston had over 43 million square feet (4,000,000 m) of office space.
Texas consisted of what type of building in the 1960's?
A: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Rajasthan's economy is primarily agricultural and pastoral. Wheat and barley are cultivated over large areas, as are pulses, sugarcane, and oilseeds. Cotton and tobacco are the state's cash crops. Rajasthan is among the largest producers of edible oils in India and the second largest producer of oilseeds. Rajasthan is also the biggest wool-producing state in India and the main opium producer and consumer. There are mainly two crop seasons. The water for irrigation comes from wells and tanks. The Indira Gandhi Canal irrigates northwestern Rajasthan.
Where does the water for cotton and tobacco come from?
A: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
After the American Revolutionary War, the number and proportion of free people of color increased markedly in the North and the South as slaves were freed. Most northern states abolished slavery, sometimes, like New York, in programs of gradual emancipation that took more than two decades to be completed. The last slaves in New York were not freed until 1827. In connection with the Second Great Awakening, Quaker and Methodist preachers in the South urged slaveholders to free their slaves. Revolutionary ideals led many men to free their slaves, some by deed and others by will, so that from 1782 to 1810, the percentage of free people of color rose from less than one percent to nearly 10 percent of blacks in the South.
What percentage of blacks in the south were free people of color after 1810?
A: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Based on discoveries made through neural mapping of the limbic system, the neurobiological explanation of human emotion is that emotion is a pleasant or unpleasant mental state organized in the limbic system of the mammalian brain. If distinguished from reactive responses of reptiles, emotions would then be mammalian elaborations of general vertebrate arousal patterns, in which neurochemicals (for example, dopamine, noradrenaline, and serotonin) step-up or step-down the brain's activity level, as visible in body movements, gestures and postures. Emotions can likely be mediated by pheromones (see fear).
What classification of chemicals do dopamine, serotonin and noradrenaline belong to?
A:
neurochemicals