(Q).
Q: By allowing blood levels of a hormone to be regulated within a narrow range, feedback loops contribute to maintaining what state? Read this paragraph and choose the correct option from the provided answers: Role of Feedback Loops The contribution of feedback loops to homeostasis will only be briefly reviewed here. Positive feedback loops are characterized by the release of additional hormone in response to an original hormone release. The release of oxytocin during childbirth is a positive feedback loop. The initial release of oxytocin begins to signal the uterine muscles to contract, which pushes the fetus toward the cervix, causing it to stretch. This, in turn, signals the pituitary gland to release more oxytocin, causing labor contractions to intensify. The release of oxytocin decreases after the birth of the child. The more common method of hormone regulation is the negative feedback loop. Negative feedback is characterized by the inhibition of further secretion of a hormone in response to adequate levels of that hormone. This allows blood levels of the hormone to be regulated within a narrow range. An example of a negative feedback loop is the release of glucocorticoid hormones from the adrenal glands, as directed by the hypothalamus and pituitary gland. As glucocorticoid concentrations in the blood rise, the hypothalamus and pituitary gland reduce their signaling to the adrenal glands to prevent additional glucocorticoid secretion (Figure 17.6). Choices: - hypothesis - hibernation - consciousness - homeostasis A:
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homeostasis

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Q: What kind of reaction adds water to an organic molecule and breaks the large molecule into smaller molecules? Read this paragraph and choose the correct option from the provided answers: A hydration reaction is the opposite of a dehydration reaction. A hydration reaction adds water to an organic molecule and breaks the large molecule into smaller molecules. Hydration reactions occur in an acidic water solution. An example of hydration reaction is the breaking of peptide bonds in polypeptides. A hydroxide ion (OH - ) and a hydrogen ion (H + ) (both from a water molecule) bond to the carbon atoms that formed the peptide bond. This breaks the peptide bond and results in two amino acids. Choices: - heat reaction - supplementation reaction - aerobic reaction - hydration reaction A:
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hydration reaction

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Q: What are groups of tens to hundreds of thousands of stars held tightly together by gravity called? Read this paragraph and choose the correct option from the provided answers: Television broadcasts also use radio waves. Sounds are encoded with frequency modulation, and pictures are encoded with amplitude modulation. The encoded radio waves are broadcast from a TV tower like the one in Figure below . When the waves are received by television sets, they are decoded and changed back to sounds and pictures. Choices: - elliptical clusters - elongated clusters - galaxy - globular clusters A:
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globular clusters