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Câu hỏi: 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.
Many flowering plants woo insect pollinators and gently direct them to their most fertile blossoms by changing the color of individual flowers from day to day. Through color cues, the plant signals to the insect that it would be better off visiting one flower on its bush than another. The particular hue tells the pollinator that the flower is full of far more pollen than are neighboring blooms. That nectar-rich flower also happens to be fertile and ready to disperse its pollen or to receive pollen the insect has picked up from another flower. Plants do not have to spend precious resources maintaining reservoirs of nectar in all their flowers. Thus, the color-coded communication system benefits both plants and insects.
For example, on the lantana, a flower starts out on the first day as yellow, when it is rich with pollen and nectar. Influenced by an as-yet-unidentified environmental signal, the flower changes color by triggering the production of the pigment anthromyacin. It turns orange on the second day and red on the third. By the third day, it has no pollen to offer insects and is no longer fertile. On any given lantana bush, only 10 to 15 percent of the blossoms are likely to be yellow and fertile. But in tests measuring the responsiveness of butterflies, it was discovered that the insects visited the yellow flowers at least 100 times more than would be expected from the haphazard visitation. Experiments with paper flowers demonstrated that the butterflies were responding to color cues rather than, say, the scent of the nectar.
In other types of plants, blossoms change from white to red, others from yellow to red, and so on. These color changes have been observed in some 74 families of plants.
The passage implies that insects would be most attracted to lantana blossoms_____
A. when they turn orange
B. on the first day that they bloom
C. on the third day that they bloom
D. after they produce anthromyacin
Many flowering plants woo insect pollinators and gently direct them to their most fertile blossoms by changing the color of individual flowers from day to day. Through color cues, the plant signals to the insect that it would be better off visiting one flower on its bush than another. The particular hue tells the pollinator that the flower is full of far more pollen than are neighboring blooms. That nectar-rich flower also happens to be fertile and ready to disperse its pollen or to receive pollen the insect has picked up from another flower. Plants do not have to spend precious resources maintaining reservoirs of nectar in all their flowers. Thus, the color-coded communication system benefits both plants and insects.
For example, on the lantana, a flower starts out on the first day as yellow, when it is rich with pollen and nectar. Influenced by an as-yet-unidentified environmental signal, the flower changes color by triggering the production of the pigment anthromyacin. It turns orange on the second day and red on the third. By the third day, it has no pollen to offer insects and is no longer fertile. On any given lantana bush, only 10 to 15 percent of the blossoms are likely to be yellow and fertile. But in tests measuring the responsiveness of butterflies, it was discovered that the insects visited the yellow flowers at least 100 times more than would be expected from the haphazard visitation. Experiments with paper flowers demonstrated that the butterflies were responding to color cues rather than, say, the scent of the nectar.
In other types of plants, blossoms change from white to red, others from yellow to red, and so on. These color changes have been observed in some 74 families of plants.
The passage implies that insects would be most attracted to lantana blossoms_____
A. when they turn orange
B. on the first day that they bloom
C. on the third day that they bloom
D. after they produce anthromyacin
Kiến thức: Đọc hiểu
Giải thích: Đoạn văn ngụ ý rằng côn trùng sẽ bị thu hút nhiều nhất bởi hoa lantana ______
A. khi chúng chuyển sang màu cam
B. vào ngày đầu tiên chúng nở hoa
C. vào ngày thứ ba chúng nở hoa
D. sau khi chúng sản xuất anthromyacin
Thông tin: For example, on the lantana, a flower starts out on the first day as yellow, when it is rich with pollen and nectar.
Tạm dịch: Ví dụ, trên lantana, một bông hoa bắt đầu nở vào ngày đầu tiên có màu vàng, khi nó rất nhiều phấn hoa và mật hoa.
Giải thích: Đoạn văn ngụ ý rằng côn trùng sẽ bị thu hút nhiều nhất bởi hoa lantana ______
A. khi chúng chuyển sang màu cam
B. vào ngày đầu tiên chúng nở hoa
C. vào ngày thứ ba chúng nở hoa
D. sau khi chúng sản xuất anthromyacin
Thông tin: For example, on the lantana, a flower starts out on the first day as yellow, when it is rich with pollen and nectar.
Tạm dịch: Ví dụ, trên lantana, một bông hoa bắt đầu nở vào ngày đầu tiên có màu vàng, khi nó rất nhiều phấn hoa và mật hoa.
Đáp án B.