Adapted from Cowboy Songs and Other Frontier Ballads by John A. Lomax (1910)

The big ranches of the West are now being cut up into small farms. The nester has come, and come to stay. Gone is the buffalo and the free grass of the open plain—even the stinging lizard, the horned frog, the centipede, the prairie dog, the rattlesnake, are fast disappearing. Save in some of the secluded valleys of southern New Mexico, the old-time round-up is no more; the trails to Kansas and to Montana have become grass-grown or lost in fields of waving grain; the maverick steer, the regal longhorn, has been supplanted by his unpoetic but more beefy and profitable Polled Angus, Durham, and Hereford cousins from across the seas. The changing and romantic West of the early days lives mainly in story and in song. The last figure to vanish is the cowboy, the animating spirit of the vanishing era. He sits his horse easily as he rides through a wide valley, enclosed by mountains, clad in the hazy purple of coming night,—with his face turned steadily down the long, long road, "the road that the sun goes down." Dauntless, reckless, without the unearthly purity of Sir Galahad though as gentle to a woman as King Arthur, he is truly a knight of the twentieth century. A vagrant puff of wind shakes a corner of the crimson handkerchief knotted loosely at his throat; the thud of his pony's feet mingling with the jingle of his spurs is borne back; and as the careless, gracious, lovable figure disappears over the divide, the breeze brings to the ears, faint and far yet cheery still, the refrain of a cowboy song.

Why does the author start the passage by listing disappearing species of the plains?

Adapted from The Story of Mankind by Hendrik Van Loon (1921)

During the first twenty years of his life, young Napoleon was a professional Corsican patriot—a Corsican Sinn Feiner, who hoped to deliver his beloved country from the yoke of the bitterly hated French enemy. But the French revolution had unexpectedly recognised the claims of the Corsicans and gradually Napoleon, who had received a good training at the military school of Brienne, drifted into the service of his adopted country. Although he never learned to spell French correctly or to speak it without a broad Italian accent, he became a Frenchman. In due time he came to stand as the highest expression of all French virtues. At present he is regarded as the symbol of the Gallic genius.

Napoleon was what is called a fast worker. His career does not cover more than twenty years. In that short span of time he fought more wars and gained more victories and marched more miles and conquered more square kilometers and killed more people and brought about more reforms and generally upset Europe to a greater extent than anybody (including Alexander the Great and Genghis Khan) had ever managed to do.

He was a little fellow and during the first years of his life his health was not very good. He never impressed anybody by his good looks and he remained to the end of his days very clumsy whenever he was obliged to appear at a social function. He did not enjoy a single advantage of breeding or birth or riches. For the greater part of his youth he was desperately poor and often he had to go without a meal or was obliged to make a few extra pennies in curious ways.

He gave little promise as a literary genius. When he competed for a prize offered by the Academy of Lyons, his essay was found to be next to the last and he was number 15 out of 16 candidates. But he overcame all these difficulties through his absolute and unshakable belief in his own destiny, and in his own glorious future. Ambition was the main-spring of his life. The thought of self, the worship of that capital letter "N" with which he signed all his letters, and which recurred forever in the ornaments of his hastily constructed palaces, the absolute will to make the name Napoleon the most important thing in the world next to the name of God, these desires carried Napoleon to a pinnacle of fame which no other man has ever reached.

The author’s purpose in the second paragraph is to __________.

Adapted from "A Very Narrow Shave" by John Lang in Adventures in Many Lands (1912)

It was a cold, clear, frosty morning when we started, the stars throbbing and winking as they seem to do only during frost, and we toiled, not particularly gaily, up the bed of a creek, stumbling in the darkness and barking our shins over more boulders and big stones than one would have believed existed in all creation. Just before dawn, when the grey light was beginning to show us more clearly where we were going, we saw in the sand of the creek fresh tracks of a large bear, the water only then beginning to ooze into the prints left by his great feet, and I can hardly say that I gazed on them with the amount of enthusiasm that Halley professed to feel.

The author’s statement that water was “only then beginning to ooze into the prints” of the bear is primarily intended to highlight __________.

Passage adapted from the Preface to The Adventures of Sherlock Holmes (1902) by Sir Arthur Conan Doyle

Some few words on the chronology of these stories may not be out of place. The first of them, "A Study in Scarlet," published in '87, was the very first separate booklet of mine that ever appeared. "The Sign of Four" followed two years later. Then, in ‘91, the “Adventures of Sherlock Holmes” began to appear in the “Strand Magazine.” The public having shown them some favour I was persuaded to continue them into another series, “The Memoirs of Sherlock Holmes,” which came to an end in 1893. That it was an end, and that I had no intention of abusing the patience of the public, was shown by the last story in which, wisely or unwisely, I brought my hero as well as my stories to an end. The subject had begun to weary me, and it seemed to me that, while there was no reason to be ashamed of doing detective stories, it was unjustifiable that I should allow myself to be tempted into doing nothing else. “The Hounds of Baskerville” represents the inevitable relapse after repentance.

Which of these best describes the author's main purpose in writing this passage?