By 60 million years ago, a distinct line of carnivorous mammals had

Question

By 60 million years ago, a distinct line of carnivorous mammals had appeared, the first of them in the shape of a weasel crossed with a cat. They were lithe, stealthy little predators, snaking through the undergrowth and tiptoeing through the canopy, each of them bearing a hallmark adaptation found about halfway back on the jaws. Opposing each other top and bottom, two large cheek teeth—later labeled the carnassials—bore cusps that had been honed to blades, coming together in a scissoring, slicing, meat-cleaving action.

Fore and aft, the carnivore mouth supplied a complete toolbox of the craft, leading the way with incisors for nipping flesh, followed by spiked canines for piercing and stabbing vital arteries and organs, ending in molars for gripping limbs and crushing bone. And invariably along the way there were those shearing carnassials. The teeth were set deeply in thick mandibles, the jaws levered by heavy temporal muscles attached to exaggerated ridges of skull bone. It was the carnivore’s Swiss-army-knife alternative to the terror birds’ basic maul of a beak.

From some such proto-carnivores arose nine major lines of meat-eaters, all but one still hunting today. They spread across the ecological spectrum, filling the land’s top predator niches. These were the ambushing cats and bone-crushing hyenas, lumbering bears and long-distance dogs. One line, on the way to becoming bears, split off and took to the water, feet morphing into the flippers of seals. Another line combined the strength of bears with the running mode of dogs to become the bear-dogs, a hybrid experiment lunging after hoofed prey across the ancient steppes of North America and Eurasia. From little slinking cats of Asia came the lion and tiger, rushing from cover and killing with suffocation throat holds. From North America grew a family of dogs, culminating size-wise in the long-legged, distance-running, gang-tacking wolf.   1 
 D 
 1. Which of the following most accurately states the purpose of the passage ? 
 
A. To compare the structural adaptations of water mammals to land mammals
B. To defend a new theory regarding the role of teeth as a defense mechanism in large predators
C. To argue against the theory of convergence in the nine major lines of mammals
D. To chronicle several events in the evolution of carnivorous predators
E. To summarize the catastrophic end to the era of dinosaurs

2  
 A 
 2. According to the passage the carnassials were

I. functionally comparative to the beak of a bird.
II. teeth set into the jaws of flesh-eating creatures.
III. a proto-species of bear-dogs that existed 60 million years ago.
IV. an organ designed to digest the ridges of skull bones.

A. I and II
B. I, II, and III
C. II and III
D. I, II, III, and IV
E. II and IV

3 
 B 
 3. It can be inferred from the passage that

A. none of the currently extant meat-eating species is descended from the original line of carnivores.
B. the modern wolf can trace its ancestry back to a weasel-resembling cat.
C. no terror-birds lived simultaneously with dinosaurs.
D. aquatic mammals are descended from a completely different ancestral line than land mammals.
E. structures in different organisms that differ in function never arise from the same progenitor.

4 
 D 
 4. It can be inferred that the author uses the word  craft  to refer to

A. the ability of a predator to snake through the forest and ambush its prey.
B. the proficiency in adjusting to the environment as animals moved from the water onto the land.
C. the expertise required to perform experiments in comparative biology.
D. the skill with which an animal is able to butcher and devour its quarry.
E. the dexterity with which mammals without opposable thumbs can adapt other digits to grasp.

5  
 D 
 5. It can be inferred from the passage that the author would agree with which of the following statements?

A. The development of carnassials conveyed an advantage to the species in which they developed in that they allowed them to use their claws to seize prey.
B. The scanty supply of food on the African plains, not sufficient to provide for big mammalian plant-eaters, was the specific cause of the rise of carnivorous mammals.
C. The survival of a species can’t be predicted from the functional relationships between abundances of species and their resources.
D. Large carnivores developed structural and behavioral mechanisms that placed them the top of the hierarchy of predators.
E. Only one remaining ancestral line of the original proto-carnivores is extant today.

Source:  Cliffs Test Prep.

RC Butler 2021  -  Practice Two RC Questions Everyday.   
Passage # 305 Date: 04-Aug-2021
 This question is a part of RC Butler 2021 .  Click here for Details

Mansi1994 · Answer

Hello Expert,

Kindly explain question 5 why option D is correct?

Sajjad1994 · Answer

Welcome to GMAT Club!

Official Explanation

5. It can be inferred from the passage that the author would agree with which of the following statements?

Difficulty Level:   700

The author suggests that large meat-eating predators rose to the top of the food chain. This can be inferred from the last paragraph:  “From some such proto-carnivores arose nine major lines of meateaters, . . . filling the land’s top predator niches.”

Choice A  is inaccurate because it refers to claws, which aren’t mentioned in the passage.

Choice B  may be true, but it isn’t discussed in the passage.

Choice C  is most likely inaccurate, but it, too, isn’t discussed in the passage.

Choice E  is inaccurate because the passage states that of the nine lines, all but one is extant. That means eight lines are still in existence.

Answer: D

By 60 million years ago, a distinct line of carnivorous mammals had

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By 60 million years ago, a distinct line of carnivorous mammals had

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615 to 715 in 15 Days (Ria's Strategies)

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