TOEFL Reading Practice Test #43

Explanation:

D is correct because paragraph 1 provides essential geographical context to help the reader understand the ecological discussion that follows.

A is incorrect because it doesn't outline the major ideas discussed later.

B is incorrect since it doesn't compare the Pacific to other oceans.

C is incorrect because the mention of island count is a detail, not the main focus.

Explanation:

C is correct because it captures both the condition (low sea levels) and the idea that species not typically suited for travel managed to colonize islands.

A leaves out the idea that some species weren't normally capable of long-distance travel.

B reverses the logic: floaters didn't need land bridges.

D contradicts the original meaning by emphasizing traits that weren’t necessary in this case.

Explanation:

B is correct because the passage states that only bats and rats succeeded in colonizing areas east of New Guinea, implying they had traits that enabled them to travel.

A is false—they did travel farther than other mammals.

C is wrong—the passage says most species came from Asia.

D is unsupported—adaptation is not discussed in this context.

Explanation:

A is correct—the passage highlights that only bats and rats managed to reach the islands.

B is not mentioned.

C contradicts the passage, which says most species came from Asia.

D is unrelated—plant suitability is not cited as the reason.

Explanation:

C is correct—the animals evolved to take the roles that mammals would usually occupy.

A is too vague and doesn’t address the ecological role.

B is irrelevant—diversity comparisons aren’t the point here.

D is close but not the main point of the example.

Explanation:

B is correct—no mammalian grazers meant no need for plant defenses.

A is unsupported.

C is wrong—chemical presence wasn’t discussed.

D misses the point—competition is not the reason for lack of defenses.

Explanation:

B is correct—birds showed no fear of humans, like domesticated animals.

A is not implied.

C and D are unrelated to the idea of ease of approach by humans.

Explanation:

D is correct—plants evolved without fire and thus were vulnerable.

A–C either misstate the comparison or aren’t mentioned.

Explanation:
[■][1] – Incorrect:
This sentence is discussing how species originally arrived on islands through natural means like floating or being digested by birds. Inserting a comparison of specific islands here would distract from that foundational explanation.

[■][2] – Incorrect:
This sentence provides geological context for why some islands were easier to reach. A specific biodiversity comparison between islands would not be appropriate here.

[■][3] – Incorrect:
Although Easter Island is mentioned here, the sentence is still discussing the mechanics of species arrival. Inserting the new sentence here would break the explanation of how geographic isolation affects colonization.

[■][4] – Correct:
This is the ideal spot because the sentence about Bougainville and Easter Island provides a concrete example that illustrates the general statement just made: that western islands have more biodiversity than eastern islands. It supports the claim with factual detail and fits smoothly into the flow.

Correct Answers:
D. Most plants and animals that have colonized Pacific islands either floated there by air or water or otherwise arrived by accident.

Explanation:
This is a central idea in paragraph 2. The passage emphasizes that species came to these islands by drifting, floating, or through birds (e.g., seeds carried in digestive tracts). It’s a foundational part of how life reached these otherwise lifeless volcanic islands.

E. Pacific islands have a large number of unique species because the organisms that colonized these islands either could fill niches normally occupied by grazing animals or had fewer competitors.

Explanation:
This aligns with the explanation in paragraph 3. Because the islands lacked mammals, birds and reptiles evolved to fill their ecological roles, leading to high levels of endemism. The lack of competition allowed these unique evolutionary developments.

F. Because most evolved outside the presence of competitors or predators such as humans, Pacific island organisms were especially likely to be damaged when exposed to such forces.

Explanation:
This is the key idea in paragraph 4. The passage discusses how the arrival of humans (a novel predator) devastated species that evolved without exposure to predators, fire, or intense competition. This is one of the main messages of the passage: extreme vulnerability due to isolation.

Incorrect Answers: 

A. Unlike most Pacific islands, which are far from land, New Zealand, Fiji, and the Solomons are continental islands.

Explanation:
While this is mentioned in paragraph 1, it is a supporting detail rather than a major idea. It sets the stage but does not contribute to the passage’s main theme about how life arrived, evolved, and responded to disturbance.

B. Despite their more specialized needs, mammals were generally more successful in adapting to eastern Pacific island ecosystems than were birds and reptiles.

Explanation:
This is factually incorrect. The passage states that mammals were largely absent from Pacific islands except for bats and rats. Birds and reptiles filled ecological niches that mammals occupied elsewhere. This choice directly contradicts the content of paragraph 2 and 3.

C. The discoveries of Charles Darwin on the Galápagos Islands pointed to a similarity in the evolution of bird and reptile species.

Explanation:
Darwin’s finches are used as an example of adaptive radiation, not to highlight similarities between birds and reptiles. The passage never compares how birds and reptiles evolved; it simply says that each evolved to fill vacant niches. This answer misrepresents the intended point.