22. Anatomical bilateral symmetry is a common trait. It follows, therefore, that it confers survival advantages on organisms. After all, if bilateral symmetry did not confer such advantages, it would not be common.

The pattern of reasoning in which one of the following arguments is most similar to that in the argument above?

(A) Since it is Sawyer who is negotiating for the city government, it must be true that the city takes the matter seriously. After all, if Sawyer had not been available, the city would have insisted that the negotiations be deferred.
(B) Clearly, no candidate is better qualified for the job than Trumbull. In fact, even to suggest that there might be a more highly qualified candidate seems absurd to those who have seen Trumbull at work.
(C) If Powell lacked superior negotiating skills, she would not have been appointed arbitrator in this case. As everyone knows, she is the appointed arbitrator, so her negotiating skills are detractors notwithstanding bound to be superior.
(D) Since Varga was away on vacation at the time, it must have been Rivers who conducted the secret negotiations. Any other scenario makes little sense, for Rivers never does the negotiating unless Varga is unavailable.
(E) If Wong is appointed arbitrator, a decision will be reached promptly. Since it would be absurd to appoint anyone other than Wong as arbitrator, a prompt decision can reasonably be expected.

23. Electrical engineers have repeatedly demonstrated that the best solid-state amplifiers are indistinguishable from the best vacuum-tube amplifiers with respect to the characteristies commonly measured in evaluating the quality of an amplifier s musical reproduction. Therefore, those music lovers who insist that recorded music sounds better when played with the best vacuumtube amplifier must be imagining the difference in quality that they claim to hear.

Which one of the following, if true, most seriously weakens the argument?

(A) Many people cannot tell from listening to it whether a recording is being played with a very good solid-state amplifier or a very good vacuum-tube amplifier.
(B) The range of variation with respect to the quality of musical reproduction is greater for vacuumtube amplifiers than for solid-state amplifiers.
(C) Some of the characteristies that are important in determining how music sounds to a listener cannot be measured.
(D) Solid-state amplifiers are more compact, use less power, and generate less heat than vacuum-tube amplifiers that produce a comparable volume of sound.
(E) Some vacuum-tube amplifiers are clearly superior to some solid-state amplifiers with respect to the laboratory to evaluate the quality of an amplifier s musical reproduction.

24. Explanation must be distinguished from justification Every human action potentially has an explanation that is with sufficient knowledge it would be possible to give an accurate description of the causes of that action. An action is justified only when the person performing the action has sufficient reasons for the action. According to many psychologists, even when there is a justification for an action, that justification often forms no part of the explanation. The general principle, however, is that only an action whose justification, that is, the reasons for the action, forms an essential part of its explanation is rational.

If the statements in the passage are correct, which one of the following can be properly concluded form them?

(A) When a human action is justified, that action has no explanation.
(B) If there are any reasons among the causes of an action, then that action rational
(C) Some psychologists believe that the justification for an action never forms an essential part of its explanation
(D) There are actions whose causes cannot be discovered
(E) If any human actions are rational then reasons must sometimes be causes of actions

25. At the company picnic all of the employees who participated in more than four of the scheduled events, and only those employees were eligible for the raffle held at the end of the day. Since only a small proportion of the employees were eligible for the raffle, most of the employees must have participated in fewer than four of the scheduled events.

Which one of the following arguments exhibits a flawed pattern of reasoning most like that exhibited by the argument above?

(A) Only third-and fourth-year students are allowed to keep cars on campus. Since one quarter of the third-year students keep cars on campus and one half of the fourth-year students keep cars on campus, it must be that fewer third-year students than fourth-year students keep cars on campus.
(B) Only those violin students who attended extra rehearsal sessions were eligible for selection as solists. Since two of the violin students were selected as soloists, those two must have been the only violin students who attended the extra sessions
(C) The only students honored at a special banquet were the band members who made the dean s list last semester. Since most the band members were honored, most of the band members must have made the dean s list.
(D) All of the members of the service club who volunteered at the hospital last summer were biology majors. Since ten of the club members are biology majors, those ten members must have volunteered at the hospital last summer
(E) All of the swim team members who had decreased their racing times during the season were given awards that no other members were given. Since fewer than half the team members were given such awards, the racing times of more than half the team members must have increased during the season