Problem: Hydrogen:

Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. The study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated synthetic pathways, which seldom involve elementary hydrogen.

What is the form of hydrogen and carbon called?
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A: hydrocarbons


Problem: Spanish language in the United States:

At over 5 million, Puerto Ricans are easily the 2nd largest Hispanic group. Of all major Hispanic groups, Puerto Ricans are the least likely to be proficient in Spanish, but millions of Puerto Rican Americans living in the U.S. mainland nonetheless are fluent in Spanish. Puerto Ricans are natural-born U.S. citizens, and many Puerto Ricans have migrated to New York City, Orlando, Philadelphia, and other areas of the Eastern United States, increasing the Spanish-speaking populations and in some areas being the majority of the Hispanophone population, especially in Central Florida. In Hawaii, where Puerto Rican farm laborers and Mexican ranchers have settled since the late 19th century, 7.0 per cent of the islands' people are either Hispanic or Hispanophone or both.

Do they speak Spanish fluently?
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A: Puerto Ricans are the least likely to be proficient in Spanish


Problem: Pain:

Although unpleasantness is an essential part of the IASP definition of pain, it is possible to induce a state described as intense pain devoid of unpleasantness in some patients, with morphine injection or psychosurgery. Such patients report that they have pain but are not bothered by it; they recognize the sensation of pain but suffer little, or not at all. Indifference to pain can also rarely be present from birth; these people have normal nerves on medical investigations, and find pain unpleasant, but do not avoid repetition of the pain stimulus.

What is the result of psychosurgery injection?
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A: unanswerable


Problem: Printed circuit board:

Often, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting can provide needed strength for components likely to endure physical stress, while components that are expected to go untouched will take up less space using surface-mount techniques. For further comparison, see the SMT page.

Which type of construction makes components that use more space?
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A:
through-hole