Câu hỏi:
13/07/2023 306Read 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.
Pollution is a threat to many species on Earth, but sometimes it can cause species to thrive. Such is the case with Pfiesteria piscicida. A one-celled creature called a dinoflagellate, Pfiesteria inhabits warm coastal areas and river mouths, especially along the eastern United States. Although scientists have found evidence of Pfiesteria in 3,000-year-old seafloor sediments and dinoflagellates are thought to be one of the oldest life forms on earth, few people took notice of Pfiesteria.
Lately, however, blooms - or huge, dense populations- of Pfiesteria are appearing in coastal waters, and in such large concentrations the dinoflagellates become ruthless killers. The blooms emit powerful toxins that weaken and entrap fish that swim into the area. The toxins eventually cause the fish to develop large bleeding sores through which the tiny creatures attack, feasting on blood and flesh. Often the damage is astounding. During a 1991 fish kill, which was blamed on Pfiesteria on North Carolina's Neuse River, nearly one billion fish died and bulldozers had to be brought in to clear the remains from the river. Of course, such events can have a devastating effect on commercially important fish, but that is just one way that Pfiesteria causes problems. The toxins it emits affect human skin in much the same way as they affect fish skin. Additionally, fishermen and others who have spent time near Pfiesteria blooms report that the toxins seem to get into the air, where once inhaled they affect the nervous system, causing severe headaches, blurred vision, nausea, breathing difficulty, short-term memory loss and even cognitive impairment.
For a while, it seemed that deadly Pfiesteria blooms were a threat only to North Carolina waters, but the problem seems to be spreading. More and more, conditions along the east coast seem to be favorable for Pfiesteria. Researchers suspect that pollutants such as animal waste from livestock operations, fertilizers washed from farmlands and wastewater from mining operations have probably all combined to promote the growth of Pfiesteria in coastal waters.
What is true of Pfiesteria?
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Trả lời:
Chọn A
Câu hỏi cùng đoạn
Câu 2:
What is the main function of the toxins emitted by the dinoflagellates?
Lời giải của GV VietJack
Chọn B
Câu 4:
Lời giải của GV VietJack
Chọn A
Câu 5:
The word "astounding" in the passage is closest in meaning to
Lời giải của GV VietJack
Chọn B
Câu 6:
According to the paragraph 2, what will NOT happen if one breathes the toxic air?
Lời giải của GV VietJack
Chọn C
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Câu 2:
Mark the letter A, B, C or D to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
I couldn't make out what he had talked about because I was not used to his accent
Câu 3:
Câu 4:
A_____is a book, film, or play that tells an exciting fictional story about something such as criminal activities or spying,
Câu 5:
I think the match____ Everybody's gone into the stadium and you can hear them cheering.
Câu 6:
Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
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