30 What does the passage mainly discuss?
(A) The history of the photoflash
(B) Theories about how the eye reacts to light
(C) The technology of modern photography
(D) The dangers of using the early photoflash

26 How did glacial meltdown affect the soil in North America? (A) It redistributed the soil types (B) It added salt to the soil (C) It made the soil more neutral in content (D) It added minerals to the soil

27 The phrase “this regionalization scheme” in line 19 refers to the (A) movements of glacial deposits (B) patterns of natural vegetation (C) human modification of the North American environment (D) distinction between humid America and arid America

28 The word “transition” in line 23 is closest in meaning to (A) elevation (B) change (C) advantage (D) condition

29 The passage supports which of the following statements? (A) Arid America is not necessarily characterized by the presence of deserts (B) Most of Canada and the northeastern United States consists of short-grass prairies wherever natural vegetation has not been modified by humans (C) The accumulation of loess is primarily the result of irrigation (D) Glaciation removed the fertile layer of soil from much of the Mississippi Valley

31 According to the passage,1/25 second is the minimum amount of time required for the (A) recording of an image on film (B) generation of artificial light (C) creation of a photographic emulsion (D) human eye to react to light

32 According to the passage, an advantage of using a photoflash is that it (A) can produce repeated bursts of light (B) intensities colors in photographs (C) is short enough not to bother human eyes (D) supplements existing lighting

33 The word “ignited” in line 9 is closest in meaning to (A) set on fire (B) cut into (C) opened (D) shaken

34 Which of the following phrases is defined in paragraph 1? (A)”appreciable period”(line 1) (B)”photographic emulsion”(line 3) (C)”high-speed movement”(line 5) (D)”odd poses”(line 11)

35 The word “evolution” in line 12 is closest in meaning to (A) publicity (B) adoption (C) development (D) manufacture

36 The function of the glass in the first flashbulbs was to (A) produce the spark that initiated the flash (B) magnify the light produced by the flash (C) protect the photographer from the heat of the flash (D) keep the metal and oxygen apart before the flash