Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg. If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space. If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae. Which of the following conclusions can properly be drawn from the information above
A. The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp’s egg-laying behavior.
B. Host insects lack any effective defenses against the form of predation practiced by parasitic wasps.
C. Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.
D. Failure to lay enough eggs would lead to the death of the developing wasp larvae more quickly than would laying too many eggs.
E. (E) Parasitic wasps use visual clues to calculate the size of host egg.
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Zelda: Dr. Ladlow, a research psychologist, has convincingly demonstrated that his theory about the determinants of rat behavior generates consistently accurate predictions about how rats will perform in a maze. On the basis of this evidence, Dr. Ladlow has claimed that his theory is irrefutably correct. Anson: Then Dr. Ladlow is not a responsible psychologist. Dr. Ladlow’s evidence does not conclusively prove that his theory is correct. Responsible psychologists always accept the possibility that new evidence will show that their theories are incorrect. Which one of the following can be properly inferred from Anson’s argument
A. Dr. Ladlow’s evidence that his theory generates consistently accurate predictions about how rats will perform in a maze is inaccurate.
B. Psychologists who can derive consistently accurate predictions about how rats will perform in a maze from their theories cannot responsibly conclude that those theories cannot be disproved.
C. No matter how responsible psychologists are, they can never develop correct theoretical explanations.
D. Responsible psychologists do not make predictions about how rats will perform in a maze.
E. (E) Psychologists who accept the possibility that new evidence will show that their theories are incorrect are responsible psychologists.
The toxin produced by certain marine snails contains various proteins, one of which, when injected into mice, made mice aged two weeks or younger fall asleep and made older mice run for hiding places. When mice are suddenly seriously threatened, very young ones react by staying perfectly still, whereas older ones run away. The facts stated above provide the strongest support for which of the following working hypotheses
A. The reaction of mice to sudden, serious threats is triggered by a chemical produced by the body, and this chemical is similar to the protein that was injected into the mice.
B. The protein contained in snail toxin that was injected into the mice ordinarily has the primary function of protecting snails by inducing in those snails complete immobility.
C. The protein that was injected into the mice would have made the mature mice fall asleep, too, if they had been injected with larger doses.
D. Very young mice are as likely to be exposed to sudden serious threats as are older mice.
E. (E) Very young mice are not developed enough to deal appropriately with even the stimuli that they are most likely to encounter.
A placebo is a chemically inert substance prescribed more for the mental relief of a patient than for its effect on the patient’s physical disorder. It is prescribed in the hope of instilling in the patient a positive attitude toward prospects for his or her recovery. In some cases, the placebo actually produces improvement in the patient’s condition. In discussing the use and effect of placebos, a well-known medical researcher recently paid physicians the somewhat offbeat compliment of saying that physicians were the ultimate placebo. By comparing a physician to a placebo, the researcher sought to imply that
A. physicians should always maintain and communicate an optimistic attitude toward their patients, regardless of the prognosis.
B. the health of some patients can improve simply form their knowledge that they are under a physician’s care.
C. many patients actually suffer from imagined illnesses that are best treated by placebos.
D. physicians could prescribe less medication and achieve the same effect.
E. (E) it is difficult to determine what, if any, effect a physician’s behavior has on a patient’s condition.
For a local government to outlaw all strikes by its workers is a costly mistake, because all its labor disputes must then be settled by binding arbitration, without any negotiated public-sector labor settlements guiding the arbitrators. Strikes should be outlawed only for categories of public-sector workers for whose services no acceptable substitute exists. The statements above best support which of the following conclusions
A. Where public-service workers are permitted to strike, contract negotiations with those workers are typically settled without a strike.
B. Where strikes by all categories of pubic-sector workers are outlawed, no acceptable substitutes for the services provided by any of those workers are available.
C. Binding arbitration tends to be more advantageous for public-service workers where it is the only available means of settling labor disputes with such workers.
D. Most categories of public-sector workers have no counterparts in the private sector.
E. (E) A strike by workers in a local government is unlikely to be settled without help from and arbitrator.
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