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Free ACT Reading and Interpreting Data practice questionsEnhanced ACT, 2026 format

Read tables and graphs from an experiment: find a value, follow a trend across rows, and interpolate or extrapolate beyond the data shown.

Answer each question, then read why the right answer is right and why the tempting one is wrong.

Question 1

Science
Students investigated factors affecting the germination of radish seeds. In each experiment, 50 seeds were placed on moist paper towels in a covered dish and kept at 22°C unless otherwise noted. A seed was counted as germinated when its root was at least 2 mm long. Germination was recorded after 72 hours.
 
Experiment 1
Seeds were kept in the dark or under continuous light. The experiment was repeated three times.
 
Table 1
Condition | Trial 1 | Trial 2 | Trial 3 | Mean germinated (of 50)
Dark | 46 | 44 | 47 | 45.7
Light | 45 | 47 | 44 | 45.3
 
Experiment 2
Seeds were kept in the dark at one of five temperatures.
 
Table 2
Temperature (°C) | Germinated (of 50)
5 | 3
12 | 21
22 | 46
30 | 48
38 | 17
 
Experiment 3
Seeds were kept in the dark at 22°C and moistened with salt solutions of different concentrations.
 
Table 3
NaCl concentration (g/L) | Germinated (of 50)
0 | 47
2 | 44
5 | 35
10 | 12
20 | 1

Based on Experiment 3, if seeds had been moistened with a 7 g/L NaCl solution, the number of germinated seeds would most likely have been:

Question 2

Science
Soil respiration is the release of carbon dioxide (CO₂) from soil by plant roots and microorganisms. Ecologists measured soil respiration rate (in grams of carbon per square meter per day, g C/m²/day) monthly for one year at three sites in a temperate forest. Site A is a mature stand of oak; Site B was clear-cut 2 years before the study; Site C was clear-cut 15 years before the study and has regrown as young maple. Table 1 gives selected monthly values.
 
Table 1
Month | Soil temp (°C) | Site A | Site B | Site C
January | 1 | 0.4 | 0.3 | 0.4
April | 8 | 1.6 | 0.9 | 1.5
July | 19 | 4.8 | 2.1 | 4.1
October | 11 | 2.2 | 1.2 | 2.0
 
The ecologists noted that root respiration accounts for roughly half of total soil respiration in intact forest.
Figure 2
00.511.522.530200400600800SiteAnnual soil respiration (g C/m²/year)Site ASite BSite C

According to Figure 2, the annual soil respiration at Site C was approximately what percentage of that at Site A?

Question 3

Science
The viscosity of a liquid is a measure of its resistance to flow; a more viscous liquid flows more slowly. Viscosity was measured for three lubricating oils at five temperatures. Results are in millipascal-seconds (mPa·s).
 
Table 1
Temperature (°C) | Oil A | Oil B | Oil C
20 | 240 | 620 | 95
40 | 110 | 250 | 55
60 | 55 | 105 | 34
80 | 30 | 48 | 22
100 | 18 | 25 | 15

As temperature increased from 20 °C to 100 °C, the difference in viscosity between Oil B and Oil C:

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