Câu hỏi:
18/11/2020 359Read the following text and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions
Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction.
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth.
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space.
The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.
The author mentions the trail pheromone of the leafcutter ant in paragraph 2 to point out
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Trả lời:
B
Kiến thức: Đọc hiểu
Giải thích:
Tác giả đề cập đến dấu vết pheromone của kiến cắn lá ở đoạn 2 để chỉ ra
A. một loại kiến phổ biến ở nhiều nơi trên thế giới
B. cần rất ít Pheromone để đánh dấu một dấu vết
C. các loại pheromones khác nhau mà kiến có thể sản sinh
D. Một số kiến có thể sản sinh đến một miligam pheromone
Thông tin: Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth.
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is CLOSEST in meaning to the underlined part in each of the following questions
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Câu 2:
Read the following pasage and decide which answer (A, B, C or D) best fits each space from 1 to 5.
With job vacancies available all year round offering high salaries, Vietnam has been ranked the second best place in the world to teach English by TEFL Exchange, a community for teachers of English (1)______ a foreign language.
The site (2)______ that a foreign English teacher can earn between 1,200-2,200 USD a month in Vietnam, where the average annual income in 2016 was just 2,200 USD. They can (3)______ a job any time of year and the best places to do so are the country’s three largest cities: Hanoi, Ho Chi Minh City and Da Nang. Candidates only need to hold a bachelor’s (4)______ and a TEFL (Teaching English as a Foreign Language) certificate.
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Điền vào ô 5.
Câu 3:
Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.
In the Egyptian calendar, the first practical calendar created, the advent of Sirius in the morning sky before sunrise marked the beginning of the annual flooding of the Nile.
Câu 4:
Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is CLOSEST in meaning to the underlined part in each of the following questions.
A striking example of a successful multiethnic country is Switzerland, where French, German, and Italian speakers from diverse religious groups live and work harmony and prosperity.
Câu 5:
Nowhere in the northern section of the United States ________ for growing citrus crops.
Câu 6:
Read the following pasage and decide which answer (A, B, C or D) best fits each space from 1 to 5.
With job vacancies available all year round offering high salaries, Vietnam has been ranked the second best place in the world to teach English by TEFL Exchange, a community for teachers of English (1)______ a foreign language.
The site (2)______ that a foreign English teacher can earn between 1,200-2,200 USD a month in Vietnam, where the average annual income in 2016 was just 2,200 USD. They can (3)______ a job any time of year and the best places to do so are the country’s three largest cities: Hanoi, Ho Chi Minh City and Da Nang. Candidates only need to hold a bachelor’s (4)______ and a TEFL (Teaching English as a Foreign Language) certificate.
English is an obligatory subject from sixth grade across Vietnam, but in large cities, many primary schools demand high (5)______. Foreign language centers have been thriving here, with students as young as three years old.
Điền vào ô 1.
Câu 7:
Read the following pasage and decide which answer (A, B, C or D) best fits each space from 1 to 5.
With job vacancies available all year round offering high salaries, Vietnam has been ranked the second best place in the world to teach English by TEFL Exchange, a community for teachers of English (1)______ a foreign language.
The site (2)______ that a foreign English teacher can earn between 1,200-2,200 USD a month in Vietnam, where the average annual income in 2016 was just 2,200 USD. They can (3)______ a job any time of year and the best places to do so are the country’s three largest cities: Hanoi, Ho Chi Minh City and Da Nang. Candidates only need to hold a bachelor’s (4)______ and a TEFL (Teaching English as a Foreign Language) certificate.
English is an obligatory subject from sixth grade across Vietnam, but in large cities, many primary schools demand high (5)______. Foreign language centers have been thriving here, with students as young as three years old.
Điền vào ô 2.
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