ACT Sample Questions

A) NO CHANGE is correct. The nonrestrictive relative clause “which stack crops in layers inside climate-controlled warehouses” is properly set off by commas on both sides. Choice B removes both commas, creating a restrictive clause that changes the meaning. Choice C changes the clause to a participial phrase, which is grammatically acceptable but changes the nuance. Choice D removes the opening comma but keeps the closing comma, creating an asymmetric error.

B) these facilities require is correct. The subject “facilities” is plural, so it requires the plural verb “require” (no “-s”). The original “requires” is a singular verb incorrectly paired with a plural subject. Choice C uses the singular “facility” with a singular verb, but “these” must precede a plural noun. Choice D combines the singular demonstrative “this” with the plural “facilities,” which is also incorrect.

A) is correct. The preceding sentence says “The idea of farming indoors is not new,” and the addition about Roman greenhouses directly supports this claim with a specific historical example. The addition is relevant and well-placed. Choice B is wrong — the sentence says nothing about renewable energy. Choice C is wrong — the addition confirms, not contradicts, that greenhouses are ancient. Choice D is wrong — the example is directly relevant to the paragraph's topic of indoor farming history.

B) is correct. When “however” introduces a sentence (used as a conjunctive adverb), it must be followed by a comma: “However, vertical farming...” The original omits this required comma. Choice C places a semicolon after “However,” which is incorrect — a semicolon is used before “however” when it connects two independent clauses within one sentence, not at the start of a new sentence. Choice D misplaces the comma after “farming.”

A) NO CHANGE is correct. The em dash introduces a clarifying phrase that emphasizes the dramatic claim. This is an appropriate use of the em dash for stylistic effect. Choice B uses a semicolon, but a semicolon must connect two independent clauses — “regardless of weather, season, or latitude” is not an independent clause. Choice C adds “whether it is,” which is redundant and awkward. Choice D is wordy and uses “everyday” (an adjective meaning “ordinary”) instead of “every day.”

B) compelling is correct. “Compelling,” “persuasive,” and “convincing” all mean essentially the same thing in this context. Using all three is redundant. The ACT tests the ability to eliminate unnecessary repetition of meaning. A single precise adjective is always preferred over a string of synonyms. Choice C retains two synonyms, which is still redundant. Choice D adds “very,” which is a weak intensifier — the ACT favors precise vocabulary over vague intensifiers.

A) NO CHANGE is correct. “Recirculated” precisely describes water being passed through the system repeatedly in a loop. Choice B (“recycled”) is less precise for water flow in a hydroponic context. Choice C (“reused again and again”) is redundant — “again and again” duplicates the meaning already present in “continuously.” Choice D (“circulated and then put back”) is awkward and wordy.

B) that are is correct. The antecedent is “carbon emissions,” which is plural, so the relative pronoun requires the plural verb “are.” Choice A (“that is”) pairs the plural “emissions” with a singular verb — incorrect. Choice C (“which is”) also uses a singular verb. Choice D (“who are”) uses “who,” which is reserved for people, not things like emissions.

A) NO CHANGE is correct. The paragraph shifts from discussing benefits to discussing a major drawback (energy consumption). “Despite these advantages” correctly signals this contrast — the criticism exists even though the advantages are real. Choice B (“Because of”) implies the advantages cause the criticism, which is illogical. Choice C (“In addition to”) suggests the criticism adds to the advantages, when it actually counters them. Choice D (“Without”) is nonsensical in context.

B) still comes is correct. The subject of this relative clause is “electricity” (singular), not “regions.” A singular subject requires a singular verb: “electricity...comes.” The phrase “in many regions” is a parenthetical interrupter set off by commas. Choice A uses the plural “come,” incorrect for singular “electricity.” Choice C shifts to progressive tense unnecessarily. Choice D (“have still come”) uses plural “have” and an awkward present perfect form.

A) is correct. The sentence gives a concrete, quantified example (carbon footprint comparison) that directly supports the paragraph's claim that vertical farming is “extraordinarily energy-intensive.” It strengthens the argument. Choice B is wrong — the sentence illustrates an argument already being made, not a new one. Choice C is wrong — this specific comparison was not made earlier. Choice D is wrong — the comparison to field-grown lettuce is directly relevant to evaluating vertical farming's environmental claims.

A) NO CHANGE is correct. When an introductory adverbial clause precedes the main clause, it is separated from the main clause by a comma. The comma after “widespread” is necessary and correct. Choice B omits this required comma. Choice C converts the verb into a participial phrase (“becoming”), which changes the grammatical structure and creates awkwardness. Choice D uses past tense (“became”), but the sentence describes a future projection, requiring present/future tense.

C) is correct. The pronoun “their” in the original is ambiguous — it could refer to the building, the solar panels, or the vertical farms. Using “its” (referring clearly to the building/facility) is more precise. The phrasing “which could make its carbon footprint negligible” is concise and clear. Choice B is verbose and redundant (“negligible and minimal” are synonyms). Choice D is also redundant (“essentially negligible and minor”). Choice A has the ambiguous pronoun “their.”

A) NO CHANGE is correct. The passage discusses vertical farming as a current, ongoing phenomenon. The simple present tense “represents” is appropriate for stating a general truth or current state of affairs. Choice B (past tense “represented”) would imply vertical farming no longer represents this experiment, which contradicts the passage. Choices C and D use perfect tenses that do not fit the present-tense context of the paragraph.

B) is correct. The original sentence has a structural error: after the participial phrase “while expensive today,” the subject “The technology” is repeated via the pronoun “it,” creating a redundant subject (“The technology...it may become”). Removing “it” fixes the sentence. Choice C splits the sentence into two independent clauses connected by “and,” which is grammatically correct but weaker — it loses the concessive nuance of “while expensive today.” Choice D omits the commas that should set off the parenthetical phrase.

B) is correct. The passage describes Asch's experimental design, findings, and later applications — this is an informative, explanatory purpose. Choice A overstates the passage's scope; it describes conformity as “troubling” but does not make a broad argument against it. Choice C mentions obedience only briefly (Milgram) and does not compare the two. Choice D is only one detail from the fifth paragraph, not the main purpose.

A) is correct. The passage states directly: “Under normal conditions, error rates were less than 1%.” This establishes the baseline before social influence. Choice B (33%) is the proportion of conforming responses across the full experiment. Choice C (75%) is the percentage of subjects who conformed at least once.

C) is correct. The passage states that some subjects “admitted they knew the group was wrong but chose to avoid conflict,” which directly supports the inference that social pressure drove conformity even when subjects privately knew the right answer. Choice A contradicts the passage's statement that the task was “unambiguous.” Choice B is not supported. Choice D describes the confederates, not the test subjects.

C) is correct. The passage states: “When even one confederate gave the correct answer — giving the subject an ally — conformity rates dropped dramatically, by more than 75%.” This is a direct detail retrieval. Choice D overstates — the passage says rates “dropped dramatically,” not that they dropped to zero.

C) is correct. In psychological research, “confederates” are people who appear to be regular participants but are actually working with the experimenter and have been given specific instructions. The passage defines this explicitly: “actors working for the researcher who had been instructed to give incorrect answers.” The other choices use alternative meanings of “confederate” (allies, voluntary participants, or the historical Civil War-era usage) that do not fit the context.

C) is correct. The passage primarily presents research findings in neutral, informative language. However, words like “troubling” and “unsettling” signal mild concern rather than pure detachment. Choice A (“prescriptive”) implies the author is telling readers what to do — the passage does not do this. Choice B is wrong — the author presents the research as valid and replicated. Choice D (“celebratory”) does not match the somewhat somber tone.

B) is correct. The passage states that “individualistic cultures (such as the United States and Western Europe) generally showing lower conformity than collectivistic cultures (such as Japan and China), though the effect was present in all groups studied.” Choice A overstates — the passage says “lower,” not “absent.” Choice C is directly contradicted by the passage. Choice D reverses the relationship described.

B) is correct. The final paragraph states that “researchers have applied his findings to understand jury decision-making, corporate groupthink, political polarization,” and spread of misinformation. These examples serve to demonstrate how widely applicable Asch's laboratory insight has proven to be. The author is not criticizing these institutions (A), claiming conformity is beneficial (C), or making any comparative argument (D).

B) is correct. The passage says Milgram “before conducting his famous obedience experiments — used Asch's methods to explore conformity in different cultural contexts.” The sequencing strongly implies Asch's work was foundational to Milgram's later, more famous experiments. Choice A conflates two distinct concepts. Choice C contradicts the cross-cultural studies mentioned. Choice D is not stated or implied.

B) is correct. “Deceptively simple” means something that looks simple but is more complex than it appears. In context, the task was objectively easy (error rate under 1%), yet it revealed profound truths about social conformity. Choice A is contradicted by the passage — the correct answer was “unambiguous.” Choice C reverses the meaning — the task was not harder than expected; it was the social dynamics that were surprising. Choice D misidentifies who was deceived (subjects, not confederates).

C) pH 7 is correct. Looking at the Reaction Rate column, the highest value is 8.5 mg/min, which corresponds to pH 7 (Trial 3). This is a straightforward table-reading question — always locate the maximum value in the relevant column. The pale yellow appearance in Trial 3 also confirms the highest level of starch breakdown.

B) 7.6 mg/min is correct. From the table: rate at pH 7 = 8.5 mg/min; rate at pH 11 = 0.9 mg/min. Difference = 8.5 − 0.9 = 7.6 mg/min. Choice C (8.5) is the rate at pH 7, not the difference. Choice A (3.2) might result from comparing pH 5 and pH 11 incorrectly (3.8 − 0.9 ≠ 3.2... watch for calculation errors).

C) is correct. The data shows: pH 3 → 1.2, pH 5 → 3.8, pH 7 → 8.5 (maximum), pH 9 → 4.1, pH 11 → 0.9. The rate increases from pH 3 to 7, then decreases from 7 to 11. This bell-shaped pattern is characteristic of enzyme activity curves, which peak at an optimal pH. This type of question tests your ability to identify a non-linear trend rather than simply comparing two values.

B) is correct. pH 6 lies between pH 5 (light blue, rate 3.8) and pH 7 (pale yellow, rate 8.5). By interpolation, we would expect a reaction rate and appearance intermediate between these two values — more breakdown than at pH 5 but less than at pH 7. This would appear between light blue and pale yellow. Choice A and D predict dark blue, which only appears at extreme pH values (3 and 11). Choice C assumes complete breakdown, which did not even occur at the optimal pH 7.

C) is correct. The description states “Temperature was held constant at 37°C,” making temperature a controlled variable — a factor deliberately kept the same across all trials to ensure the experiment tests only the effect of pH. Choice A (pH) is the independent variable — it was intentionally varied. Choice B (reaction rate) is the dependent variable — it was measured as the outcome. Choice D (appearance) is also a dependent variable, observed alongside reaction rate.

B) is correct. This is a scientific reasoning question about the limits of evidence. The experiment tested only amylase, which shows optimal activity at pH 7. However, the student's claim is about ALL enzymes in the human body — a much broader claim. A single experiment on one enzyme cannot support or refute a universal claim about all enzymes. This is a classic ACT Science reasoning question: the data is valid, but it does not address the full scope of the claim. (In reality, stomach enzymes work best near pH 2, and intestinal enzymes work best near pH 8.)

B) is correct. To test the effect of temperature on amylase activity, temperature must be the independent variable (changed across trials) while all other variables are held constant. This includes holding pH constant — and pH 7 is the logical choice since it was shown to be optimal, eliminating pH as a confounding factor. Choice A tests a different enzyme, not temperature. Choice C changes two variables simultaneously (pH and temperature), making it impossible to isolate the effect of either one. Choice D uses only one temperature, providing no basis for comparison.