True of the merchants out of a conflict between the

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Unformatted text preview: ation research is called upon to demonstrate successes or failures of social programs. Yet this rush into practical applications is itself quite understandable: public policy must continually be made, and policymakers rightly feel that even tentative findings and untested theories are better guides to decision-making than no findings and no theories at all. (123 words) 105 Zooplankton, tiny animals adapted to an existence in the 10. It can be inferred from the passage that which of the ocean, have evolved clever mechanisms for obtaining their following is true of appendicularians? food, miniscule phytoplankton (plant plankton). A very specialized feeding adaptation in zooplankton is that of the (A) They are exclusively carnivorous. tadpolelike appendicularian who lives in a walnut-sized (or (B) They have more than one method of obtaining smaller) balloon of mucus equipped with filters that capture food. and concentrate phytoplankton. The balloon, a transparent (C) They can tolerate frigid water. structure that varies in design according to the type of (D) They can disguise themselves by secreting appendicularian inhabiting it, also protects the animal and mucus. helps to keep it afloat. Water containing phytoplankton is (E) They are more sensitive to light than are other pumped by the appendicularian‘s muscular tail into the zooplankton. balloon‘s incurrent filters, passes through the feeding filter where the appendicularian sucks the food into its mouth, and then goes through an exit passage. Found in all the oceans of the world, including the Arctic Ocean, appendicularians tend to remain near the water‘s surface where the density of phytoplankton is greatest. (143 words) 106 Exercise 19 The common cold, produced most often by rhinoviruses, is intractable to antiviral defense. A defense against 1. It can be inferred from the passage that a cell lacking delta-receptors will be rhinoviruses might nonetheless succeed by exploiting (A) unable to prevent the rhinoviral nucleic acid hidden similarities among the rhinovirus strains. For from shedding its capsid example, most rhinovirus strains bind to the same kind of (B) defenseless against most strains of rhinovirus molecule (delta-receptors) on a cell‘s surface when they (C) unable to release the viral progeny it develops attack human cells. Colonno, taking advantage of these after infection common receptors, devised a strategy for blocking the (D) protected from new infections by antibodies attachment of rhinoviruses to their appropriate receptors. to the rhinovirus Rather than fruitlessly searching for an antibody that would bind to all rhinoviruses, Colonno realized that an antibody (E) resistant to infection by most strains of rhinovirus binding to the common receptors of a human cell would prevent rhinoviruses from initiating an infection. Because 2. It can be inferred from the passage that the purpose of Colonno‘s experiments was to determine whether human cells normally do not develop an...
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This document was uploaded on 09/16/2013.

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