17. All of the following could be considered examples of exogenous influences on an organism EXCEPT the influence of the
(A) level of a hormone on a field mouse's readiness for mating
(B) temperature of a region on a bear's hibernation
(C) salt level of a river on a fish's migration
(D) humidity of an area on a cat's shedding of its fur
(E) proximity of an owl on a lizard's searching for food
18. Which of the following statements best describes the conclusion drawn by Brown (lines 14-17)?
(A) A change in tide schedule is the primary influence on an oyster's rhythms.
(B) A change in tide schedule may be an important exogenous influence on an oyster's rhythms.
(C) Exogenous influences, such as a change in tide schedule, seldom affect an oyster's rhythms.
(D) Endogenous influences have no effect on an oyster's rhythms.
(E) Endogenous influences are the only influences on an oyster's rhythms.
19. The passage suggests that Brown's study was similar to Hamner's in which of the following ways?
Ⅰ. Both experimenters discovered that a new environment had a significant effect on an organism's behavioral rhythms.
Ⅱ. Both experimenters observed an organism's behavioral rhythms after the organism had been transported to a new environment.
Ⅲ. Both experimenters knew a organism's rhythmic patterns in its original environment.
(A)Ⅰonly
(B)Ⅱonly
(C)Ⅰand Ⅱ only
(D)Ⅱand Ⅲ only
(E)Ⅰ,Ⅱ,and Ⅲ
20. Which of the following, if true, would most weaken Brown's conclusion?
(A) The oysters gradually closed their shells after high tide in Illinois had passed.
(B) The oysters' behavioral rhythms maintained their adaptation to the tide schedule in Illinois throughout thirty days of observation.
(C) Sixteen days after they were moved to Illinois, the oysters opened their shells widest when it was high tide in Connecticut.
(D) A scientist who brought Maryland oysters to Maine found that the oysters opened their shells widest when it was high tide in Maine.
(E) In an experiment similar to Brown's, a scientist was able to establish a clear causal relationship between environmental change and behavioral rhythms.
Picture-taking is a technique both for annexing the objective world and for expressing the singular self. Photographs depict objective realities that already exist, though only the camera can disclose them. And they depict an individual photographer's temperament discovering itself through the camera's cropping of reality. That is, photography has two antithetical ideals: in the first, photography is about the world and the photographer is a mere observer who counts for little; but in the second, photography is the instrument of intrepid, questing subjectivity and the photographer is all.
These conflicting ideals arise from a fundamental uneasiness on the part of both photographers and viewers of photographs toward the aggressive component in "taking" a picture. Accordingly, the ideal of a photographer as observer is attractive because it implicitly denies that picture-taking is an aggressive act. The issue, of course, is not so clear-cut. What photographers do cannot be characterized as simply predatory or as simply, and essentially, benevolent. As a consequence, one ideal of picture-taking or the other is always being rediscovered and championed.
An important result of the coexistence of these two ideals is a recurrent ambivalence toward photography's means. Whatever the claims that photography might make to be a form of personal expression on a par with painting, its originality is inextricably linked to the powers of a machine. The steady growth of these powers has made possible the extraordinary
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