ACT Past Papers with Answers

Paper 47 · ACT June 2013 · Form 71C · Science Test

Source question 2. Refer to the source image.

Paper 47 · ACT June 2013 · Form 71C · Science Test

The change in the mass of the cylinders was callsed by the absorption of the deicer into the concrete. Based on Figure 2, the cylinders submerged in which deicer had absorbed, on average, the greatest mass of deicer at 250 days? Key deiceT . Mgcl Cacl - Nacl Ca(OH)2

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based orA the infonnation provided, how many grams of solid Nacl would have had to be dissolved in water to prepare 1,000 grams of the Nacl deicer? 15g 30g i(x) 21x1 300 subrnersion time (days) 500

Paper 47 · ACT June 2013 · Form 71C · Science Test

In the studies, it is most likely that the cylinders were submerged in deicers at 4°C because that temperature is: the freezing point of water. a typical summer temperature in areas where deirers are used. a typical winter temperature in areas where deicers are used. Figure 3 Flgur8s adapted from Lawrence Suttèr et al.. 'The D81eterious Chemlcal Effects of Concentrated Deicing Solutlons on Portland Cemenl Concrete," South Dakota Department of Transportation siudy SD2002-01. 2008.

Paper 47 · ACT June 2013 · Form 71C · Science Test

For pavement made of the same concrete as the cylin- ders, the minimurn CS that is required to maintain a smooth, uncracked road surface is 25 MPa. Based on th¢ iesults of Study 2, which deicer(s) could most likely be kept in contact with this concrete continu- ously for 600 days without low￿1ng the average CS of the concrete below 25 MPa ? .F. Nacl only l. According to Figure I, for ally subrnersion time after O days, what is the order of the 4 deicers. from the deicer that produced the greatest average percent change in cylinder length to the deicer that produced the least average percent change in cylinder length? 4ooooooooc4 Passage 11 When the nucleus of an atom of a radioactive isotope underooeq certain types of decay, the atom transforms into an atom of a different isotope. An isotope's half-life is the time it takes for half of any given number of its nuclei to decay. An isotope's deca)s constant, k. depends on the iso- tope's rate of decay. Table I gives the value of X (in yr ) for 8 isotopes of different elements. 1,000 900 800 700 600 500 400 300 200 100 Table I Fe-59 Element Isotope Ni-63 Ti-44 Sr-90 Nickel Titaniurn Strontium Hydrogen Sulfur Iron Phosphorus iodine 0,024 0 20 40 60 80 100 120 140 160 180 200 time (days) S-35 Fe-59 P-32 1-131 Figure 2 18 32 Fitrures l and 2 show, for each of 6 of the isotopes listed in Table I, the change over time in the number of the lluclei reinaining, N, in a sample initially containing 1,000 of the nuclei,

Paper 47 · ACT June 2013 · Form 71C · Science Test

The data in Figure 2 for tirne= 140 days are best showll by whicb of the following graphs? 400 400 (Note: In Figllre I, the unit of time is years; in Figure 2, the unit of time is days.) 1,000 900 800 700 600 500 .400 300 200 100 200 100 100 400 200 0 20 40 60 80 100 120 140 160 180 200 time (yr) 100 100 Figure I 40000000004

Paper 47 · ACT June 2013 · Form 71C · Science Test

According to Figure 2, for which isotope. S-35 or P-32. will the average rate of decay be greater over the flrst 200 days? will have the lower N,. will have the higher N,. will have the lower N,. will have the higher N,.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on Table l and Figure I, if a sample initially contains 1.000 Ti-44 atoms, tbe number of Ti-44 atoms ID tlie sample 20 yr later will most likely be:

Paper 47 · ACT June 2013 · Form 71C · Science Test

According to Figure l. the half-life of Si-90 is appIoximately: 30 yr. 90 yr. 200 yr.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based oll Figure 2, if a sample contained ZO fro of .Fe-59 at time- O, at approximately wnat w&ll the,N, ol-the samptc be 400 ? 40 days 60 days 80 days 40000000004 Passage111 Transferrin is a blood protein. When in the presence 3+ of iron ions (Fe ). each transferrin molecule will bind with 3+ 2 Fe . Iron chelators are used to remove excess iron in tbe blood because they can bind with and thereby remove Fe from transfettin. ' defer()xamllie TRENCAM 3+ Transferrin bound to Fe strongly absorbs light at a wavelength of 466 nanometers (nm), but unbound transfer- 3+ rin and unbound Fe do not. Three experiments were done llsing a colorimeter (a device that measuTes a solution's 3+ absorbance of light) to study. the removal of Fe fiom transferrin by iron chelators. 02 TREN.HOPO defenproné 2,000 time (sec) 3,Tr)0 4,000 Experiment J Seven solutions (Solutions 1-7) were made, all with an initial unbound transferrin concentration of

Paper 47 · ACT June 2013 · Form 71C · Science Test

When a colorimeter is used. a solution called a blank is first placed in the colorimeter to establish a baseline value against which other solutions will be measured. Which of the solutions served as the blank?

Paper 47 · ACT June 2013 · Form 71C · Science Test

In each trial of Experiments 2 alld 3. how often was all absorbance measurement recorded?

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on the experiments, as the conceDtratiOD of Fe bound to transferrin in a solution decreases, the absorbance: increases onIy. varies. but with no general trend. remains constant.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on the results of Experiments 2 and 3,. the &verage rate of change in the absorbance during the TREN-HOPO trial was closest to that observed during the trial with what other iron chelator and at what temperature? TRENCAM at 37°C

Paper 47 · ACT June 2013 · Form 71C · Science Test

sup.pose that in Experiment I, 10 ML of Solution 2 had been mixed with 10 ML of Solution 4 after the solu- tions were incubated. If the absorban¢e of a.s.ample of the resulting solution had been measuTed at 37"C,' it would most likely have been closest to which of the following.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on the description of Experiment l and of a col- orimeter, the material making up th'e test tube that was placed in the colorniieter most likely: absorbed little or. no light at 466 nm. reflected all light that was less than 466 nm. 40000000004 Passage IV Study 2 With the aluminum coil, the students heated ethylene glycol for 10 mill at each of the values of I selected in Study l. For each value of I, they computed AT. They did likewise with vegetable oil. substituting it for the ethylene glycol. Plots of A T versus I for water (from Figure l), the ethylene glycol. and the vegetable oil are shown in Figure 2. In 2 studies, students recorded the temperature changes that occurred in different liquids when the liquids were heated for l O min each by various metal coils throuEh which selected amounts of electrical curren¢ I, flowed. For each trial in the studies, tbe students carried out the following procedure: Firs¢ they poured 400 ML of a liquid into an insulated container fitted with a thern]ometer and a metal coil and sealed the container (see. diagram). Key -￿ water ethylene glycol vegetable oil therMon￿ter insulation liquid metal coil 40 wire 30 20 ammeter magnetic stirrer magnet power supply diagram of apparatus 10 With the liquid, the container, and the coil at ioom temper- ature, 25°C, the students began to stir the liquid with a magnetic stiTrer. Next, they adjusted the voltage across the ends of the coil until I reacbed the desired value, in amps (A). For the next 10 min, they continued to stir the liquid. After 10 min of heating, they recorded T, the liquid's temperature, in °C, and computed AT, the differ- ence between T and the.liquid's initial temperature of 25'C.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Accoiding to the results of the studies, for a given coil and a given liquid, as th¢ currellt that passed through the coil was increased, ￿T. increased only. varied. but with no general trend. remained the same. tungstett. 40 30

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on the results of the studies, to obtain the lowest T after 10 min of heating at a given I using the appa- ratus diagrammed in the passage, the students should select which liquid and which metal coi17 uid metal coil 10

Paper 47 · ACT June 2013 · Form 71C · Science Test

The students stirred each liquid for which of the fol- lowing Ieasons? throughout the liq￿d the container coil

Paper 47 · ACT June 2013 · Form 71C · Science Test

Suppose thal in Sthdy l. the students had also tested a coil made of a fouttb meta]. Metal X, at l= 1.5 A. and detenDined tbat after 10 n]in of heating, AT was 6°C. Based on Fi.(FUte l. rf the students had next tested the Metal X coil at 1= 2.0 & LIT after 10 min of beating would most ]￿e1)I have been:

Paper 47 · ACT June 2013 · Form 71C · Science Test

.Based on the results of Study 2, when vegetable oil was heated with l- 1.5 A, T at the end of 10 min was closest to which of the following.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Suppose thaL in a new study, the tungsten coil with 1= 2.0 A is used to heat 200 ML of water. After the water is heated for 10 min, will most likely be: 40000000004 Passage V Hypothesis 4 Botulin is absorbed from the synaptic cleft by the muscle fiber. Botulin then binds to and breaks down myosin, a Protein that is an essential component of the con- tractiie apparatlls of a muscle fiber. As a result of this breakdown, the muscle fiber callnot contract. Introduction skeletal neuromuscular junction (NMJ"" see the figure) is composed of a synaptic terminal (a tip of an axon of a n¢uron), a motor end plate (a depression in the plasma membrane of a muscle fiber), and a syrtaptic cleft (the region between these 2 structures). The synaptic tern]inal contains synaptic vesicles: structures that contsin the neu- rotransrnitter acetylcholine (Ach). When the neuron [￿es. synaptic vesicles fuse wtth the neuron's plasma membrane and release Ach into the synaptic cleft. Ach then diffiises across the synaptic cleft and binds to Ach receptors (mem- brane proteins produced by the muscle fiber) in the Motor end plate. If this binding does not occur, the muscle fiber cannot contract. synaptic clefi

Paper 47 · ACT June 2013 · Form 71C · Science Test

Both Hypothesis l and Hypothesis 4 indicate that, in the human body, botulin is: excreted before it enters the digestive tract. synaptic vesicles containing Ach Ach receptor

Paper 47 · ACT June 2013 · Form 71C · Science Test

Which of the following statements best characterizes Ach as it is described in the introduction? a muscle fiber to a synaptic tenninal. a synaptic terniinal to a muscle fiber, tion from a muscle fiber to a synaptic terniinal. tion from a synaptic tern]inal to a muscle fibeT.

Paper 47 · ACT June 2013 · Form 71C · Science Test

An acetylcholinesterase 15 a molecule that binds to and breaks down Ach. Which hypothesis indicates that botulin functions like an acetylcholinesterase7

Paper 47 · ACT June 2013 · Form 71C · Science Test

In which of the following ways do Hypotheses 3 and 4 differ with regard to how botulin disru ts ]lluscIc coll- ttaction? Hypothesis 3 asserts that botu in: plasma membrane of a neuron" Hypothesis 4 asserts that botulin blocks Acb binding sites. contractile apparatus of a muscle fiber; Hypoth- esis 4 asserts that botulin blocks Ach binding sites. that botulin breaks down a protein that partially composes the plasma membrane of a neuron. that botulin breaks down a protein that partially cornposes the contractile apparatus of a muscle fiber. synaptic motor terminal end plate If a person ingests botuzin (a toxin), it enters the bloodstream, diffuses into NMJ synaptic clefts, and dis- rupts the contraction of the muscle fibers associated with these NMJS. Four hypotheses propose mechanisms for the disruption of function at an NMJ. HypothÉsis I Botulin is absorbed from the synaptic cleft by the synapti¢ tern]inal. Botulin then binds to and breaks down the neuron's docking PTOteins (proteins required for the fusion of synaptic vesicles with the neuron's plasma rneEQ- brane). Because the vesicles cannot fuse with.the plasma membrane, they cannot release Ach into the synap¢.ic cleft. Thus, Ach does not bind to the Ach receptors. Therefore. the muscle fiber cannot contract. Hypothesls 2 Botulin remains ill the Syllaptic cleft, where it binds to and breaks down Ach before the Ach can diffiise across the synaptic cleft and bind to the Ach receptors. Therefore. the muscle fiber cannot contract. Hypothesis 3 Botulin remains in the Syllaptic ¢left, where it,binds to and irreversibly blocks the Ach receptors. As a result, Ach cannot bind to the Ach receptors. Therefore,. the muscle fiber cannot contract. 40000000004

Paper 47 · ACT June 2013 · Form 71C · Science Test

In which of the following ways does Hypothesis I differ from the other 3 hypotheses with regard to the location in the body where botulin is likely io be found after it is consumed? Only Hypothesis l asserts that botulin enters..

Paper 47 · ACT June 2013 · Form 71C · Science Test

Ac¢ording to Hypotheses 3 and 4, which of the follow- illg statements best describes a step in the mechanism that results in the disruption of function at an NMJ by botulin? fiber. synthesized by a muscle fibei. synthesized by a neuroa. 4 。 。 。 。 。 。 。 。 。 4 Passage VI Tasters are people who can taste Chemical P. Non­ tasters are people who cannot taste Chemical P.The ability to taste Chemical P is determined by Gene T, which has 2 alleles: Tand t. In a population that is not evolving—a population in Hardy-Weinberg equilibrium(HWE)一the frequency of allele Tis pand the frequency of allele tis q. Table 1 shows the Gene T genotype(s) of tasters and of nontasters and theexpression that predicts the frequency of each genotype in a population in HWE.Table 2showsp, q, and the frequency of each Gene T genotype for 4 popula­ tions in HWE. Table 1 Phenotype Genotype Frequency Taster TT p2 Taster Tt 2pq Nontaster tt q2 Table 2 Frequency of: Population p q TT Tt tt 1 0.5 0.5 0.25 0.50 0.25 2 0.4 0.6 N.P. 0.48 0.36 3 0.8 N.P. 0.64 0.32 0.04 4 N.P. N.P. 0.09 0.42 0.49 Note: N.P. indicates that the value has not been provided.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Which hypothesis would be best supported by the find- ing tbat botulin has a high affinity for the Ach recep- tors in a motor elld plate? neurons. muscle fibers.

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on Table 2, in which population would the num­ ber of people with the genotype TTand·the number of people with thegenotype ttbe closest to the same? . A. Population 1

Paper 47 · ACT June 2013 · Form 71C · Science Test

The frequency of nontasters is greatest in which population?

Paper 47 · ACT June 2013 · Form 71C · Science Test

A student concluded that for Population 3, pis greater than q.Is this conclusion consistent with Table 2?

Paper 47 · ACT June 2013 · Form 71C · Science Test

For Population 2, genotype TT? what is the frequency of the

Paper 47 · ACT June 2013 · Form 71C · Science Test

People that are heterozygous for Gene T are most common in the population for which pis: 气 ` , \ \ ` ` r " 2 i j ' - i ” 上 L , L \ ＇ 、 1 , ： ｀ . ？ ' , . ，' ． ， 飞 ＇ ｀ 飞 ． ， ， ＇ ＇ ， `～． 赈 ACT-71C 48 GO ON TO THENEXT PAGE. ~、~、 -－Z-－－ . . ， ．， ＇ ` , ．． s t i ” t ' 卢， ＇ 4 t ; . ， I '＇ ， ' ， , ． , . 4o 。 。 。 。 。 。 。 o4 Passage VII When an object floats in a liquid, a fraction of the object extends above the surfaceof the liquid. Seven objects with different densities were placed in containers of 4 different liquids. Table 1 lists the obje�ts 3 and their densities, in grams per cubic centimeter (g/cm�), at 15° Table 1 Object D(g e / n cm sity 勺 1 0.100 2 0.200 3 0.300 4 0.400 5 0.500 6 0.600 7 0.700 Table2 lists the 4 liquids and their densities, in g/cm3 , at 15° Table2 Liquid D(g e / n cm sit 勺 y Crude oil 0.87 Gasoline 0.74 Mercury 13.6 Water 0.99 Figure 1 shows竺 for each liquid, a graph of the fraction of each object extending a玩ove the liquid's surface versus the object's density, in g/cm气 芍 0 1.00 口总 ;;.:� mercury §卫。．80』---�．一···································································· 芍贮“0.60➔ 肆 ························-··-••"U,,••················································· 甘二 、water 吕 秤 0001 .，＼；:$$; l °$、 求求森求＠、 心、 七令9§ 、S 、· `. 、.、． 、. 、. 、． 、． 、· objectdensity {g/cm勺 Figure 1

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on Figure I, for each liquid, as object density increased, the fraction of the object extending above theHquid's surface:

Paper 47 · ACT June 2013 · Form 71C · Science Test

Based on Table I and Figure 1, the fraction ofObject 6 extending above the surface of the crude oil was clos­ est to which of the following values?

Paper 47 · ACT June 2013 · Form 71C · Science Test

A material composing a cube has a density of 3

Paper 47 · ACT June 2013 · Form 71C · Science Test

Suppose anobject with a density of 0.99 g/cm3 floats in a container of water, and both the object and the water are at 15° object and the water are raised to 90° C, and if the object neither expands nor contracts with the change in temperature, will the object more likely sink or remain afloat? than the object. than the object. more dense than the object. dense than the object.

Paper 47 · ACT June 2013 · Form 71C · Science Test

What is the meaning of the value for the density of mercury that is given in Table2 ? . 3 旦One cm: of mercury has a volume of 13.6 g. of mercury has a mass of 13.6 g. END OFTEST4 STOPI DO NOT RETURN TO ANY OTHER TEST. Text Form 18L ACT Wri�ing Test Prompt (June 2013) Educators debate whether high school students should have _an active role in classroom instruction, such as selecting some course materials and leading some class discussions. Some educators support giving students an active role in classroom instruction because they think doing so would increase students'interest in their classes. Other educators do not support giving students an active role in classroom instruction because they think·students would not learn as �uch from their peers as they would from a teacher� In your opinion, should high ·school students have an active role in classroom instruction? In your essay, take a position on this question. You may write about either one of the two points of view given, or you may present a different pointof view on this question. Use specific reasons and examples to support your position. 、 ＿ ｀ ｀飞．，＇ 52 . : ; l . . “ : ; ？ ? 20136ACT+71C,#$ English Mathematics Readling Science 1 B 36 F 1 A 31 E 1 C 1 A 2 F 37 D 2 K 32 J 2 H 2 G 3 D 38 G 3 B 33 C 3 A 3 A 4 H 39 D 4 F 34 J 4 H 4 H 5 B 40 H 5 A 35 E 5 D 5 D 6 F 41 B 6 K 36 G 6 H 6 J 7 B 42 J 7 B 37 B 7 B 7 D 8 G 43 C 8 H 38 H 8 H 8 H 9 D 44 H 9 B 39 B 9 B 9 C 10 F 45 D 10 H 40 F 10 G 10 F 11 C 46 J 11 D 41 A 11 A 11 D 12 J 47 D 12 H 42 G 12 F 12 F 13 D 48 F 13 B 43 C 13 C 13 C 14 F 49 C 14 G 44 F 14 G 14 G 15 A 50 J 15 D 45 B 15 C 15 C 16 J 51 B 16 H 46 H 16 J 16 G 17 B 52 F 17 D 47 D 17 A 17 A 18 F 53 D 18 F 48 H 18 J 18 F 19 B 54 G 19 E 49 A 19 B 19 A 20 F 55 A 20 J 50 F 20 F 20 G 21 C 56 H 21 A 51 C 21 A 21 C 22 J 57 C 22 J 52 K 22 H 22 G 23 C 58 H 23 A 53 D 23 A 23 D 24 G 59 A 24 H 54 K 24 G 24 F 25 D 60 F 25 D 55 D 25 A 25 D 26 J 61 C 26 K 56 G 26 J 26 G 27 A 62 G 27 E 57 C 27 A 27 D 28 H 63 B 28 H 58 K 28 G 28 G 29 B 64 F 29 B 59 A 29 C 29 A 30 J 65 D 30 G 60 K 30 J 30 H 31 C 66 G 31 D 31 A 32 F 67 C 32 H 32 J 33 C 68 F 33 D 33 B 34 F 69 C 34 F 34 F 35 B 70 F 35 A 35 C 71 C 36 J 36 G 72 G 37 B 37 C 73 C 38 G 38 H 74 G 39 C 39 B 75 A 40 J 40 J Explanation of Procedures Used to Obtain Scale Scores from Raw Scores On each of the four tests on which you marked any responses, the total number of correct responses yields a raw score. Use the table below to convert your raw scores to scale scores. For each test, locate and circle your raw score or the range of raw scores that includes it in the table below. Then, read across to either outside column of the table and circle the scale score that corresponds to that raw score. As you determine your scale scores, enter them in the blanks provided on the right. The highest possible scale score for each test is