AccelePrep for the ACT Test 2nd Edition Student Text

C HAPTER 11 | H YPER P REP S CIENCE • 221

Scientist 2 The prevailing opinion is that the atmosphere, though thicker now than it was in the past, is not essentially different in composition. The ƒ”‰—‡– –Šƒ– ƒ”–Š —•– ‘”‹‰‹ƒŽŽ› Šƒ˜‡ „‡‡ †‡ϐ‹…‹‡– ‹ ‘š›‰‡ ‹• ϐŽƒ™‡†Ǥ ‹”•–ǡ –Š‡ ’”‡•‡…‡ ‘ˆ ‹”‘ ƒ† ‘–Š‡” ‘š‹†‡• ‹ –Š‡ ”‘…• ˆ”‘ –Š‹• time indicates that there was oxygen available. Second, the requirement for a great deal of ultraviolet light holds only if there is a low concentration of the starting materials in the water. If the water in some prehistoric lake began to freeze, the starting materials would be concentrated in a small volume of unfrozen water. The high concentration of the starting materials ™‘—Ž† ‘ˆˆ•‡– –Š‡ •‘Ǧ…ƒŽŽ‡† †‡ϐ‹…‹‡…› ‘ˆ —Ž–”ƒ˜‹‘Ž‡– Ž‹‰Š–ǡ ƒ† Ž‹ˆ‡…‘—Ž† begin. 3. Underlying Scientist 1’s suggestion that the evolutionary record •—’’‘”–• –Š‡ ‹†‡ƒ ‘ˆ ƒ ‘š›‰‡ †‡ϐ‹…‹‡…› ‘ ‡ƒ”Ž› ƒ”–Š ‹• –Š‡ assumption that the oldest living things: A. have the shortest DNA. B. have the most fragmented DNA. C. have changed radically. D. must have died out. 4. Underlying the argument of Scientist 2 is the assumption that the oxygen in the oxides in the rocks was: F. always tied up in the rocks. G. involved in biological reactions. H. completely gaseous during the early days of the atmosphere. J. related to the oxygen in the atmosphere at the time. Picking the Best Argument items ask for the argument that best supports or undermines the hypothesis. Concentrate on the central point of the hypothesis and any assumptions that were made regarding the data. Since an assumption is the weakest part of a hypothesis, it will have the greatest impact on the hypothesis whether the argument supports or undermines it. 5. To refute Scientist 1’s hypothesis, Scientist 2 might best show that: A. the amount of oxide in rocks has changed little over the past four billion years. B. there are ways of making the biologically important molecules without ultraviolet light. C. there are complex anaerobic bacteria. D. the atmospheric pressure has not changed over Earth’s history.

PICKING THE BEST ARGUMENT

Examples: