Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
Swans are among the most beautiful of North American waterfowl and have always enjoyed the admiration and even the protection of bird lovers. Of the six species in the swan genus, only two are native to North America. The trumpeter swan, the largest of the group, breeds in the northern United States and Alaska, and was nearly wiped out during the nineteenth century craze for elaborately feathered hats. The whistling swan, which winters in large flocks on the Chesapeake Bay, has recently been renamed the tundra swan because it breeds and summers on the northernmost tundra regions of the continent.
Recently, populations of mute swans - an exotic species introduced to North America from Europe in the early 1900s - have begun increasing by an alarming 30 to 40 percent annually in some states. Most wildlife biologists today believe the majestic white creatures, with their tendency to destroy a pond's plant life and drive away native waterfowl, might create havoc on the scale of the gypsy moth, starling, or English sparrow.
Both native species of swans are wild and require large areas of uninhabited summer ground for nesting and feeding. Mutes, however, semi-domesticated and accustomed to people, can nest in pairs of as many as three or four on one small coastal pond, which can burden delicate and environmentally essential brackish ponds.
According to the passage, the main issue concerning mute swans is that they are ________________.
A.not native to North America
B.semi-domesticated
C.possessive of their habitat
D.increasing very rapidly
Swans are among the most beautiful of North American waterfowl and have always enjoyed the admiration and even the protection of bird lovers. Of the six species in the swan genus, only two are native to North America. The trumpeter swan, the largest of the group, breeds in the northern United States and Alaska, and was nearly wiped out during the nineteenth century craze for elaborately feathered hats. The whistling swan, which winters in large flocks on the Chesapeake Bay, has recently been renamed the tundra swan because it breeds and summers on the northernmost tundra regions of the continent.
Recently, populations of mute swans - an exotic species introduced to North America from Europe in the early 1900s - have begun increasing by an alarming 30 to 40 percent annually in some states. Most wildlife biologists today believe the majestic white creatures, with their tendency to destroy a pond's plant life and drive away native waterfowl, might create havoc on the scale of the gypsy moth, starling, or English sparrow.
Both native species of swans are wild and require large areas of uninhabited summer ground for nesting and feeding. Mutes, however, semi-domesticated and accustomed to people, can nest in pairs of as many as three or four on one small coastal pond, which can burden delicate and environmentally essential brackish ponds.
According to the passage, the main issue concerning mute swans is that they are ________________.
A.not native to North America
B.semi-domesticated
C.possessive of their habitat
D.increasing very rapidly
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