Experts have differed about where the genus Varanus (monitor lizards)

Question

Experts have differed about where the genus Varanus (monitor lizards) originated. Because most existing species live in Australia, early researchers concluded that Varanus originated in Australia and subsequently island hopped westward along the Indo-Australian archipelago. Herpetologist Robert Mertens later argued that Varanus probably originated in the archipelago. Chromosomal analysis has since supported Mertens’ contention, and in addition,  geologic evidence  points to a collision between the archipelago and the Australian landmass afer Varanus evolved—a fact that could account for the genus’ present distribution. A related puzzle for scientists is the present distribution of Varanus’ largest surviv ing species, the Komodo dragon. Tese carnivores live only on four small islands in the archipelago where, scientists note, the prey base is too small to support mammalian carnivores. But the Komodo dragon has recently been shown to manage body temperature much more efciently than do mammalian carnivores, enabling it to survive on about a tenth of the food energy required by a mammalian carnivore of comparable size.    1 
 1. It can be inferred from the passage that the geographical distribution of the Komodo dragon is

A. currently less restricted than it was at the time researchers frst began investigating the origins of the genus Varanus
B. currently more restricted than it was at the time researchers frst began investigating the origins of the genus Varanus
C. less restricted than is the distribution of the genus Varanus as a whole
D. more restricted than is the distribution of the genus Varanus as a whole
E. viewed as evidence in favor of the hypothesis that the genus Varanus originated in the Indo-Australian archipelago

2  
 2. Which of the following elements in the debate over the origin of Varanus is NOT provided in the passage?

A. The evidence that led Mertens to argue that Varanus originated in the Indo-Australian archipelago
B. The evidence that led early researchers to argue that Varanus originated in Australia
C. A possible explanation of how Varanus might have spread to the IndoAustralian archipelago if it had originated in Australia
D. A possible explanation of how Varanus might have spread to Australia if it had originated in the Indo-Australian archipelago
E. An indication of the general present-day distribution of Varanus species between Australia and the Indo-Australian archipelago

3  
 3. It can be inferred that which of the following is true of the “geologic evidence” ( Highlighted )?

A. It was frst noted by Mertens as evidence in favor of his theory about the origins of Varanus.
B. It cannot rule out either one of the theories about the origins of Varanus discussed in the passage.
C. It accounts for the present distribution of the Komodo dragon.
D. It has led to renewed interest in the debate over the origins of Varanus.
E. It confrms the conclusions reached by early researchers concerning the origins of Varanus.

Sajjad1994 · Answer

The passage begins by identifying a question that has long puzzled scientists. The first paragraph is devoted to considering two possible answers to the question. The second paragraph introduces a question that is related to the question discussed in the first paragraph. It then provides a possible answer to it.

OE

1. It can be inferred from the passage that the geographical distribution of the Komodo dragon is

Choice D  is correct. Because the Komodo dragon, a species of Varanus, is restricted to  “four small islands in the archipelago”  but  “most existing species”  of the genus Varanus as a whole live in Australia, the geographical distribution of the genus includes species in both places. The distribution of the Komodo dragon is restricted to only one of these places and is thus more restricted than the genus as a whole, not less restricted. Thus,  Choice C  is incorrect.  Choices A  and  B  are incorrect because the passage does not describe the specifc change in the geographic distribution of the Komodo dragon, but rather just describes its present distribution.  Choice E  is incorrect because the passage does not present its discussion of the Komodo dragon as evidence for either hypothesis of the origin of Varanus but rather as a  “related puzzle.”  
 
  Answer: D

Sajjad1994 · Answer

OE

2. Which of the following elements in the debate over the origin of Varanus is NOT provided in the passage?

Choice A  is correct. The passage provides support for Mertens’ argument by providing later chromosomal evidence as well as geologic evidence but it does not provide nor describe the evidence with which Mertens originally argued.

Choices B  and  E  are incorrect because the passage states that early researchers argued for a specifc origin for Varanus  “because most existing species live in Australia,”  which indicates the present-day distribution of species.

Choices C  and  D  are incorrect because the passage provides geologic evidence to suggest a possible explanation for how  Varanus  may have spread to either Australia or the archipelago regardless of its origin. 
 
  Answer: A

Sajjad1994 · Answer

OE

3. It can be inferred that which of the following is true of the “geologic evidence” (     Highlighted     )?

Choice B  is correct. The passage presents the  “geologic evidence”  so as to provide a possible explanation for the prevalence of the various species of Varanus in Australia if indeed Mertens’ theory is correct. But the evidence itself does not rule out the possibility that the earlier theory is correct and that Mertens is not, so the  “geologic evidence”  cannot rule out either theory.

Choice A  is incorrect because there is no specifc indication that Mertens frst provided this evidence, and the chronology of the presentation suggests that he did not.

Choice C  is incorrect as the Komodo dragon lives only in the archipelago, and  Choice D  is incorrect as there is no mention in the passage of a specifically renewed interest in the debate.

Choice E  is incorrect since the  “geologic evidence”  does not rule out nor confrm either Mertens’ conclusions or those of earlier researchers. 
 
  Answer: B

Experts have differed about where the genus Varanus (monitor lizards)

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