This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Q: Serotonin is a neuromodulator involved in regulation of mood and behavior. Development in the limbic system plays an important role in determining rewards and punishments and processing emotional experience and social information. Changes in the levels of the neurotransmitters dopamine and serotonin in the limbic system make adolescents more emotional and more responsive to rewards and stress. The corresponding increase in emotional variability also can increase adolescents' vulnerability. The effect of serotonin is not limited to the limbic system: Several serotonin receptors have their gene expression change dramatically during adolescence, particularly in the human frontal and prefrontal cortex .

A: Which neuromodulator is involved in regulation of mood and behavior?
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Q: The Maya writing system (often called hieroglyphs from a superficial resemblance to the Ancient Egyptian writing) was a combination of phonetic symbols and logograms. It is most often classified as a logographic or (more properly) a logosyllabic writing system, in which syllabic signs play a significant role. It is the only pre-Columbian writing system known to represent completely the spoken language of its community. In total, the script has more than one thousand different glyphs although a few are variations of the same sign or meaning and many appear only rarely or are confined to particular localities. At any one time, no more than about five hundred glyphs were in use, some two hundred of which (including variations) had a phonetic or syllabic interpretation.

A: What is the Mayan writing system the only known pre-Columbian one to completely represent this?
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Q: In cpDNA, there are several A → G deamination gradients. DNA becomes susceptible to deamination events when it is single stranded. When replication forks form, the strand not being copied is single stranded, and thus at risk for A → G deamination. Therefore, gradients in deamination indicate that replication forks were most likely present and the direction that they initially opened (the highest gradient is most likely nearest the start site because it was single stranded for the longest amount of time). This mechanism is still the leading theory today; however, a second theory suggests that most cpDNA is actually linear and replicates through homologous recombination. It further contends that only a minority of the genetic material is kept in circular chromosomes while the rest is in branched, linear, or other complex structures.

A:
What kind of gradients does cpDNA have?
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