ACT Past Papers with Answers

Paper 16

ACT April 2021

Form D05 · Science Test · 40 questions

Back to sections

Tools:

Paper 16 · ACT April 2021 · Form D05 · Science Test

Based on Figure 2, on how many dates each year is solar time exactly 8 minutes behind mean time?

A2B4C6D8

Tools:

Paper 16 · ACT April 2021 · Form D05 · Science Test

What was the average CT, in kilograms (kg), for fish kept at a temperature of 22°C and a salinity of 25 ppt ? 41 GO ON TO THE NEXT PAGE. ACT-D05 4 4 Passage III Three studies examined the effects of compost (organic matter) on 3 physical properties of soil. Five soil mixtures (Mixtures 1−5) were prepared (see Table 1). Study 1 A 1.5 L pot was prepared by placing 500 g of Mixture 1 into the pot, after which the pot was stored at 30°C for 72 hr. The pot and its contents were then baked in a 105°C oven for 24 hr. After cooling, the mixture’s bulk density (the dry mass of the mixture per unit volume) was determined. These procedures were repeated for each of Mix- tures 2−5 (see Table 2). Study 2 Another 1.5 L pot of Mixture 1 was prepared, stored, and baked as in Study 1. The dried mixture was ground into powder and passed through a screen with 2 mm diameter openings. Five grams of the screened powder were then mixed with 5 mL of H2O, and the pH of the powder-H2O suspension was determined. These procedures were repeated for each of Mix- tures 2−5 (see Table 3). Study 3 Another 1.5 L pot of Mixture 1 was prepared, stored, and baked as in Study 1. The dried mixture was then ground and screened as in Study 2. Fifty grams of the screened powder were mixed with 5 mL of H2O to form a soil paste, and the paste was placed on a filter. Suction was then applied to the filter, and the extract (the clear, colorless liquid that passed through the filter) was collected. The electrical conductivity of the extract was determined. These procedures were repeated for each of Mix- tures 2−5 (see Table 4). Table 1 Mixture Percent by volume of: compost soil 1 05 95 2 25 75 3 50 50 4 75 25 5 95 05 Table 2 Mixture Bulk density (mg/mL) 1 104 2 159 3 213 4 255 5 302 Table 3 Suspension of H2O and Mixture: pH 1 6.5 2 6.2 3 6.7 4 7.0 5 7.2 Table 4 Extract from Mixture: Electrical conductivity (dS/m*) 1 2.40 2 2.56 3 3.45 4 2.15 5 1.86 *decisiemens per meter 42 GO ON TO THE NEXT PAGE. ACT-D05 4 4

A0000,0.0521 kgB0000,0.521 kgC00,052.1 kgD52,100.0 kg

Tools:

Paper 16 · ACT April 2021 · Form D05 · Science Test

Consider the statement “The percent by volume of compost in the mixture that had the greatest bulk den- sity was the same as the percent by volume of compost in the mixture that had the extract with the lowest elec- trical conductivity.” Do the results of Studies 1 and 3 support this statement? greatest bulk density and the lowest electrical conductivity. greatest bulk density and the lowest electrical conductivity. greatest bulk density, but 95% by volume of com- post resulted in the lowest electrical conductivity. greatest bulk density, but 50% by volume of com- post resulted in the lowest electrical conductivity. 43 GO ON TO THE NEXT PAGE. ACT-D05 4 4 Passage IV When a sand-covered drumhead vibrates at certain frequencies, the sand collects at nodes (areas of least vibra- tion). Two types of nodes can form on a vibrating drum- head: radial nodes, which look like rings, and linear nodes, which look like straight lines. As sand collects at nodes, patterns called nodal patterns (NPs) form. Figure 1 shows two NPs that can form on a sand-covered drumhead: NP 1 (a radial node only) and NP 2 (a radial node and a linear node). Figure 1 Students performed 2 experiments to study the forma- tion of NP 1 and NP 2 on various drumheads. Experiment 1 The students obtained 5 drumheads, each having a dif- ferent diameter and each set to a tension of 2,000 newtons per meter (N/m). They performed a trial with each drum- head, using the following procedure: First, they placed the drumhead directly above a speaker emitting sound waves having a frequency of 90 hertz (Hz). Then, they gradually increased the frequency until they observed NP 1. Finally, they continued to increase the frequency until they observed NP 2. Throughout each trial, the amplitude (loud- ness) of the sound waves was held constant. Table 1 shows the frequency at which the students observed NP 1 and NP 2 for each trial. Experiment 2 The students performed 7 more trials with the 50 cm diameter drumhead. In each trial, first the tension was adjusted to a certain value, and then the procedures of the Experiment 1 trials were repeated. Figure 2 shows the results for each trial, as well as a line of best fit for each NP. Figure 2

AYes; 50% by volume of compost resulted in theBYes; 95% by volume of compost resulted in theCNo; 50% by volume of compost resulted in theDNo; 95% by volume of compost resulted in the

Tools:

Paper 16 · ACT April 2021 · Form D05 · Science Test

A student claimed that the greater the drumhead diam- eter, the longer the wavelength of sound needed to observe a given NP. Is this claim supported by the results for NP 2 from Experiment 1 ? at which NP 2 was observed increased. at which NP 2 was observed decreased. at which NP 2 was observed increased. at which NP 2 was observed decreased. 45 GO ON TO THE NEXT PAGE. ACT-D05 4 4 Passage V Three students observed that Trait R is present in some people but not in others. The presence or absence of Trait R in a person is determined entirely by alleles of Gene R. Gene R has 2 alleles: R, which is dominant, and r, which is recessive. A teacher gave the students a pedigree showing the inheritance of Trait R in a particular family (see Figure 1). Each individual represented in the pedigree was assigned a number (shown below the symbol for the individual) for reference. Based on the pedigree, each student proposed a hypothesis explaining the pattern of inheritance for Trait R in this family. 46 GO ON TO THE NEXT PAGE. ACT-D05 4 4 Figure 1 2 1 14 15 16 17 3 4 18 19 5 6 22 23 8 9 7 20 21 24 25 26 27 10 11 12 13 28 Key without Trait R with Trait R mating offspring male female Student 1 Gene R is located on the X chromosome, so females (who inherit two X chromosomes) inherit 2 copies of Gene R, whereas males (who inherit one X chromosome) inherit only 1 copy of Gene R. All females with Trait R inherited 2 copies of the r allele, and all males with Trait R inherited 1 copy of the r allele. Table 1 shows the possible Gene R genotypes for females and for males and indicates whether the genotypes result in Trait R. Table 1 Gender Gene R genotype Trait R present? Female RR Rr rr no no yes Male R* r* no yes *Because males inherit only one X chromosome, their Gene R genotype has only 1 copy of Gene R. Student 2 Gene R is not located on the X chromosome or the Y chromosome. All individuals with Trait R inherited 2 copies of the r allele. Student 3 Gene R is not located on the X chromosome or the Y chromosome. All individuals with Trait R inherited either 1 or 2 copies of the R allele.

AYes; as the diameter was increased, the frequencyBYes; as the diameter was increased, the frequencyCNo; as the diameter was increased, the frequencyDNo; as the diameter was increased, the frequency

Tools:

Paper 16 · ACT April 2021 · Form D05 · Science Test

Consider Individuals 3 and 4 and their offspring. Is this portion of the pedigree more consistent with the hypothesis of Student 1 or the hypothesis of Student 3 ? that Trait R is a dominant trait. that Trait R is a recessive trait. that Trait R is a dominant trait. that Trait R is a recessive trait. Gene R genotype Trait R present? RR yes Rr yes rr yes Gene R genotype Trait R present? RR yes Rr yes rr no Gene R genotype Trait R present? RR yes Rr no rr no Gene R genotype Trait R present? RR no Rr no rr yes 47 GO ON TO THE NEXT PAGE. ACT-D05 4 4 Passage VI The hot, spicy flavor of chili peppers is directly pro- portional to the concentration of capsaicinoids (a class of chemical compounds). Scientists studied the effects of fer- tilizer application and pepper color on the capsaicinoid concentration of 3 varieties of chili peppers (V1−V3). Study Two hundred V1 plants that were 82 days old were divided into 4 equal groups, and each group was planted in a different plot (Plot L, M, N, or O) in a particular field. This procedure was repeated with V2 and V3 plants in sep- arate, but adjacent, fields. Fertilizer was then applied to the type L plots and the type M plots. Each plot was irrigated equally once every 20 days until harvest. All the peppers in the type L plots and the type N plots were harvested 77 days after planting, while the peppers were still green. All the peppers in the type M plots and the type O plots were harvested 87 days after planting, after the peppers had turned red. Table 1 summarizes, for each plot type, whether fertilizer was applied to the plot and the color of the pep- pers in the plot at the time of harvest. Immediately after being harvested, all the peppers were dried at 65°C for 24 hr. Then, for each field, all the dried peppers grown in a given plot were ground up and combined. The total capsaicinoid concentration, in mil- ligrams of capsaicinoids per gram of dry pepper (mg/g), was then determined for the peppers from each plot of each field. The results are shown in Table 2. Tables adapted from Alberto González-Zamora et al., “Measurement of Cap- saicinoids in Chiltepin Hot Pepper: A Comparison Study between Spec- trophotometric Method and High Performance Liquid Chromatography Analysis.” ©2015 by Alberto González-Zamora et al. Table 1 Plot type Fertilizer applied? Pepper color at harvest L yes green M yes red N no green O no red Table 2 Pepper variety Plot Total capsaicinoid concentration (mg/g) V1 L M N O 078 060 070 055 V2 L M N O 105 087 092 072 V3 L M N O 087 049 071 030 48 GO ON TO THE NEXT PAGE. ACT-D05 4 4

AStudent 1; this portion of the pedigree suggestsBStudent 1; this portion of the pedigree suggestsCStudent 3; this portion of the pedigree suggestsDStudent 3; this portion of the pedigree suggests

Form D05 · Science Test · 40 questions

1 / 40