## 1.

The Correct Answer is (B) — (B) is the correct answer. The passage is mainly concerned with different research on balancing a bicycle, enumerating various analyses of the mechanisms of balance and the physics behind it. (A) is incorrect because it is too broad; the passage is focused not on balance in general, but on balancing a bicycle. (C) is incorrect because the researchers in the passage are concerned with balance, which is where their interest in bicycle design stems from—they are not primarily concerned with bicycle design itself, nor do they suggest that bicycle design is an “underappreciated field.” (D) is incorrect because, though the passage mentions steering in lines 30–55, it does not suggest that novice riders balance better, nor is this a primary focus of the passage.

## 2.

The Correct Answer is (G) — (G) is the correct answer. The author here uses the example of the broomstick as an analogy for bicycle riding, noting that “steering a bicycle is equivalent to the hand motions required to keep the broomstick balanced” (lines 36–38). Thus, the mention of the broomstick functions as a supporting metaphor, making (G) correct. (F) is incorrect because the broomstick is not a personal anecdote, or story, from the author. (H) is incorrect because the broomstick is used as a supporting detail, not as a counterexample. (J) is incorrect because the lines after 36-38continue to discuss steering; the mention of the broomstick does not signal a change in direction in the passage.

## 3.

The Correct Answer is (A) — (A) is the correct answer. Lines 7–11 discuss how “using mathematical equations, researchers have explained how a bicycle without a rider can balance itself and have identified the bicycle design features critical for that to happen.” The next lines, however, note that quantifying the stability and balance of a rider is more difficult than quantifying the balance of a bicycle alone. Thus, these lines provide a contrast between a phenomenon researchers can explain and one they cannot, making (A) the best choice. (B) is incorrect because while the rest of the passage does discuss balance and steering, the main purpose of the examples here is to set up a contrast; the shift of focus to human balancing on bicycles comes later. (C) is incorrect because the author is not suggesting manufacturers should alter their bicycle designs. (D) is incorrect because the author is briefly mentioning two phenomena, not detailing extensive research.

## 4.

The Correct Answer is (H) — (H) is the correct answer. In the final paragraph, the author notes further directions for and applications of research into balancing on bicycles, indicating that researchers still have more areas to explore. Thus, (H) is correct. (F) is incorrect as the paragraph mentions nothing about bias. (G) is incorrect because the author ends on an optimistic note about research, and doesn’t indicate he believes such research is futile, or ineffectual. On the contrary, he notes that “with such measurements, we could identify riders at high risk of falling, explore the extent to which bicycle design can reduce fall risk and increase balance performance, and develop the mathematical equations that describe riders of different skill levels” (lines 66–71). (J) is incorrect because the author mentions specific ways bicycle research could help riders, which means he believes in its practicality.