Question

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.

It’s a sound you will probably never hear, a sickened tree sending out a distress signal. But a group of scientists has heard the cries, and they think some insects also hear the trees and are drawn to them like vulture to a dying animal. Researchers with the US Department of

Agriculture’s Forest Service fastened sensors to the bark of drought-stricken trees clearly heard distress calls. According to one of the scientists, most parched trees transmit their plight in the 50-hertz to 50-kilohertz range. (The unaided human ear can detect no more than 20 kilohertz). Red oak, maple, white pine, and birch all make slightly different sounds in the form of vibrations at the surface of the wood.

The scientists think that the vibrations are created when the water columns inside tubes that run along the length of the tree break, a result of too little water following through them. These fractured columns send out distinctive vibration pattems. Because some insects communicate at ultrasonic frequencies, they may pick up the trees' vibration and attack the weakened trees. Researchers are now running tests with potted trees that have been deprived of water to see if the sound is what attracts the insects. “Water-stressed trees also smell differently from other trees, and they experience thermal changes, so insects could be responding to something other than sound”, one scientist said.

Which of the following could be considered a cause of the distress signals of trees?

A. attacks by insects

B. experiments by scientists

C. torn roots

D. lack of water

Answer 1

Đáp án D

Vấn đề nào sau đây có thể được coi là nguyên nhân gây ra tín hiệu đau khổ của cây?

A. các cuộc tấn công bởi côn trùng

B. các thí nghiệm của các nhà khoa học

C. rễ bị đứt

D. thiếu nước

Thông tin ở câu: “The scientists think that the vibrations are created when the water columns inside tubes that run along the length of the tree break, a result of too little water following through them.” (Các nhà khoa học nghĩ rằng những rung động được tạo ra khi các cột nước bên trong các ống mà chạy dọc theo chiều dài của cây bị phá vỡ, là kết quả của việc quá ít nước chảy qua chúng.)