The Correct Answer is (A) — The question asks you to identify how Scientist 1 uses the crater in Mexico as evidence for one of his arguments. The crater is identified as the place where the earth was struck by an asteroid, and its existence proves that the asteroid did impact the earth. (B) and (D) are incorrect since there is no mention of greenhouse gases or fossilized plants in Scientist 1’s passage. (C) is incorrect because the shocked quartz is used in conjunction with the crater to prove that the asteroid strike did happen, and the crater is not used as an evidence for the existence of shocked quartz.
The Correct Answer is (H) — The question asks you to identify Scientist 2’s explanation for the extinction of the carnivores. The text emphasizes that “without [the plants], herbivores and carnivores soon” disappeared, directly linking the disappearance of plants to that of carnivores. (F) is incorrect since it is stated in the passage that the extinction was a “gradual decrease”---carnivores were not suddenly burned by lava. (G) is incorrect because the trapped sunlight led to the heating of the earth, not the burning of carnivores. (J) is incorrect because it is never mentioned in the text that iridium may be poisonous.
The Correct Answer is (B) — The question asks whether a suggestion that the KT extinction was caused by competition for scarce resources is consistent with the given viewpoints. The given hypothesis agrees with Scientist 2’s viewpoint since Scientist 2’s description of volcanic activity also implies a long-term competition for scarce resources: the “gradual decrease” of herbivores and carnivores was caused by the scarcity of plants, which are crucial resources for the nourishment of herbivores. (A) and (C) are incorrect because the question specifies that the extinction happened “over millennia”, which directly contradicts the “relatively fast extinction” described by Scientist 1.
The Correct Answer is (F) — The question asks you to predict how Scientist 1, who supports the asteroid hypothesis, would explain volcanic activity in India. The asteroid came first according to Scientist 1, so it would make sense for this scientist to say that an asteroid impact could cause the later occurring volcanic activity in that area. (G) may be tempting; however, it is incorrect because there is no evidence of volcanic activity all over the world, and also large amounts of volcanic activity can make Scientist 2’s hypothesis more convincing than that of Scientist 1. (H) is incorrect since there is no indication of how volcanic activity can possibly cause asteroid impacts. (J) is incorrect since it does not link the given situation to Scientist 1’s argument as it does not mention the asteroid.
The Correct Answer is (C) — The question asks you what Scientist 1 would predict as the result of increasing smog, which blocks sunlight. Scientist 1 directly states that the blocking of the sun causes the cooling of the earth. (D) is the exact opposite of the correct answer. (A) and (B) are incorrect since the passage does not discuss the effect of a lack of sunlight on currently fossilized species, but rather on the process of fossilization (and therefore on future fossilized species).
The Correct Answer is (J) — The question asks you to identify a piece of evidence found in the layer of Earth’s crust used by Scientist 1 and not Scientist 2. Scientist 1 uses impact ejecta as proof for an asteroid impact. Iridium levels, shocked quartz, and a decrease in fossilized species are all used by Scientist 2 to explain their viewpoint, so (F), (G), and (H) are all incorrect.
The Correct Answer is (C) — The question asks you to analyze another mass extinction event, and determine whether the presence of iridium and shocked quartz is consistent with the viewpoints of either scientist. Scientist 1 uses iridium and shocked quartz to show that the extinction was caused by an asteroid. Scientist 2 uses these two pieces of evidence to support the hypothesis that volcanic activity caused the extinction. Therefore, the data is consistent with both of the viewpoints, eliminating (A), (B), and (D).
The Correct Answer is (F) — The question asks you to identify the hypothesis that argues that viruses descend from prokaryotes. Hypothesis 1 explicitly states that “viruses descended from living prokaryotes.” (G) is incorrect---although Hypothesis 2 accepts that viruses appear to have evolved, it does not specify whether they have descended from prokaryotes. (H) is incorrect since Hypothesis 3 argues that prokaryotes evolved from viruses, not vice versa.
The Correct Answer is (C) — The question asks you to identify hypotheses which assert that viruses have not diversified over time. (A) and (D) are incorrect since Hypothesis 1 makes no assertions about the diversification of viruses. Hypothesis 2 asserts that viruses have “retained the complex phylogenetic history of the multicellular organisms”, which suggests that they have not diversified. The definition of phylogenetic history from the passage shows that the fact that viruses don’t have their own phylogenetic histories means that they have not evolved through diversification. Hypothesis 3 directly states that “virions [...] have remained the same since”. Therefore, 2 and 3 agree with the given statement, and (C) is correct.
The Correct Answer is (J) — The question asks you to identify a common property of viruses and prokaryotes based on the passage and three hypotheses. (F) and (G) are incorrect since the first paragraph of the passage asserts that the genetic information of a virus can be in the form of RNA or DNA---it isn’t in the form of only one. (H) is incorrect since a second membrane is never mentioned. (J) is correct because the first paragraph of the passage, as well as the first paragraph of Hypothesis 1 suggest that both viruses and prokaryotes have a single membrane around their genetic material.
The Correct Answer is (D) — The question asks you to identify a cladogram which agrees with the phylogenetic history of viruses based on Hypothesis 3 alone. According to Hypothesis 3, active viruses and prokaryotes both descended from virions, so virions should be on the left of the cladogram with a branch for each descendant. Hypothesis 3 then goes on to explain that multicellular organisms came from prokaryotes, so a branch should extend from prokaryotes to demonstrate this. (A) and (B) are incorrect because they do not show active viruses, prokaryotes, and multicellular organisms evolving from virions. (C) is incorrect because it shows multicellular organisms descending from active viruses.
The Correct Answer is (G) — The question asks you to identify which hypothesis would be most weakened by the discovery of a larger virus which contains proteins necessary for reproduction. Hypothesis 2 argues that viruses have never been alive and are nothing more than scraps of genetic material---this is contradicted by the existence of an advanced virus capable of reproduction. (F) is incorrect since Hypothesis 1 argues that viruses are alive, and used to be capable of reproducing on their own, which is strengthened by the discovery of viruses that can reproduce. (H) is incorrect since Hypothesis 3 also asserts that viruses are living organisms, which is supported by their ability to reproduce.
The Correct Answer is (B) — The question asks you to identify the most effective treatment against viruses according to Hypothesis 2. Hypothesis 2 states that viruses are collections of RNA, DNA and proteins from other organisms. Therefore, a treatment destroying these would be effective against viruses. (A) is incorrect, since Hypothesis 2 states that viruses are not living cells. (C) is incorrect since the Lytic Cycle is the method by which viruses reproduce, which would only make a viral infection more serious if amplified. (D) is incorrect since viruses are different than prokaryotes, and they are not related according to Hypothesis 2.
The Correct Answer is (F) — This is a knowledge question which asks you to identify the organelle responsible for photosynthesis. From your Biology courses, you may remember that this is called a chloroplast. Mitochondria are responsible for energy production in both plant and animal cells, vacuoles are storage bubbles in a cell, and centrosomes are used in cell division.
The Correct Answer is (B) — The question asks you to identify which student(s) would agree with the suggestion that the increase in carbon dioxide (CO2) levels has caused the increase in temperature. Student 1 states that an increase in temperature causes an increase in carbon dioxide levels so you can eliminate (A) and (C). Student 2 suggests that increased carbon dioxide levels directly lead to higher temperatures, so (D) is incorrect, and you’re left with (B).
The Correct Answer is (H) — The question asks you to determine a statement which would match Student 1’s interpretation of the graph as it relates to the current average temperature of the atmosphere. (F) is incorrect, as Student 1 states that “historical peaks in atmospheric temperature” have been this high before. (G) is incorrect, as the student mentions that the temperatures have been similar “on at least three other occasions”. (J) is incorrect since the student never suggests that the values have been exceeded - he states that they have “reached levels similar to those observed recently”.
The Correct Answer is (D) — The question asks you to determine a prediction that Student 1 would be likely to make about the next 100,000 years of climate data. The student predicts that the previous trend of “random fluctuations” will continue in the future. (A) and (B) are incorrect because they suggest a constant trend of either decreasing or increasing CO2 and temperature levels. (C) is incorrect since the student suggests that temperature and CO2 levels are directly correlated, and they cannot move independently.
The Correct Answer is (F) — The question asks you to determine what Student 1 would predict to be the most likely result of temperature increases. Student 1 asserts that increasing temperatures slow down plant metabolisms, and the question tells you that plant metabolisms produce oxygen. Therefore, increased temperature leads to lower levels of oxygen. (G) is incorrect as it contradicts this relationship. (H) is incorrect because it is explicitly stated that temperature changes affect plant metabolisms, which affect oxygen production. (J) is incorrect because such a drastic effect is never suggested.
The Correct Answer is (C) — The question asks you to choose Student 1’s prediction regarding the effects of the reduction of fossil fuels. Student 1 believes that the climate fluctuates randomly, so would say that reducing fossil fuels would have no effect on global climate change. (A), (C), and (D) are incorrect as they suggest that Student 1 thinks there is a relationship between climate change and fossil fuel usage.
The Correct Answer is (J) — The question asks you to determine the effects of the climate scientist’s model on the arguments of the two students regarding the relationships between carbon dioxide levels and temperature. Both of the students agree that temperature and carbon dioxide levels are directly correlated, and increase and decrease together. This suggests that the study will have the same effect on both viewpoints, strengthening or weakening both at the same time. This allows you to eliminate (G) and (H). The graph shows temperature increasing and carbon dioxide levels decreasing as you go further into the past---this contradicts the students’ arguments that the two quantities are directly correlated. Therefore, the argument is weakened, and (F) is incorrect.
The Correct Answer is (C) — This question asks you to identify the gases which consist of single elements on the periodic table, as those will not act as greenhouse gases. Argon gas is composed of only Ar, which suggests that it is not a greenhouse gas. This eliminates option (B). Nitrogen gas is composed of two nitrogen particles, which are only one element; therefore, it is not a greenhouse gas, and you can eliminate option (A). Water is composed of multiple elements---hydrogen (H) and oxygen (O); therefore, it can act as a greenhouse gas, eliminating (D).
The Correct Answer is (C) — (C) is the correct answer. The lines in answer (C) refer to the bats’ behaviors with the clicking moths, and about the bats losing track of the moths they were hunting, so it matches the correct answer to the previous question. (A) refers to one of the disproved hypotheses about the clicking defense, not the behavior the study uncovered, so it is incorrect. (B) refers to how bats would behave if a different hypothesis were true, not to how they actually behaved, so it is incorrect. (D) refers to the general mechanism bats use to hunt moths, not to why they did not attack certain moths, so it is incorrect.
The Correct Answer is (A) — This question requires you to consider the relationships between characters in the passage. (A) is correct because, even though Mr. Bloom mocks the cat for its fear of chickens, his affectionate treatment of it throughout the passage shows that he loves his pet. He gets down on his hands and knees to meet the cat’s eye-level, admires its shiny coat, and even states that cats “understand what we say better than we understand them” (lines 31-32 (B) and (E) are incorrect because, as argued above, Mr. Bloom is fond of his cat and doesn’t “revile” it (think it is despicable) or want to replace it. (C) is incorrect because this is exactly the opposite of what Mr. Bloom expresses about his cat in this sentence, which is that his cat is the stupidest cat he’s ever seen. (D) is incorrect because it corresponds to other parts of the passage, not to the quotation this question asks about. In this line, Mr. Bloom only calls the cat “stupid.” He does say it is “Vindictive” and “Cruel” in the previous paragraph, but “stupid” does not mean the same thing as either of these.