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 from 30 to 34.
Genetic modification of foods is not a new practice. It has been practiced for thousands of years under the name of "selective breeding". Animals and plants were chosen because they had traits that humans found useful. Some animals were larger and stronger than others, or they yielded more food, or they had some other trait that humans valued. Therefore, they were bred because of those traits. Individuals with those traits were brought together and allowed to breed in the hope that their offspring would have the same traits in greater measure.
Much the same thing was done with plants. To produce bigger or sweeter fruit, or grow more grain per unit of land, strains of plants were combined and recombined to produce hybrids, or crossbreeds that had the desired traits in the right combinations. All the while, however, biologists wondered: is there a more direct and versatile way to change the traits of plants and animals? Could we rewrite, so to speak, the heredity of organisms to make them serve our needs better?
In the 20th century, genetic modification made such changes possible at last. Now, it was possible to alter the genetic code without using the slow and uncertain process of selective breeding. It even became possible to blend plants and animals genetically: to insert animal genes into plants, for example, in order to give the plants a certain trait they ordinarily would lack, such as resistance to freezing. The result was a tremendous potential to change the very nature of biology
The word "them" in paragraph 2 refers to ______.
A. organisms
B. traits
C. animals
D. plants
Chọn A
Kiến thức: Đọc hiểu
Giải thích:
Từ “them” trong đoạn 2 đề cập tới?
A. organisms (n): sinh vật
B. traits (n): đặc điểm
C. animals (n): động vật
D. plants (n): thực vật
Thông tin: Could we rewrite, so to speak, the heredity of organisms to make them serve our needs better?
Tạm dịch: Chúng ta có thể viết lại, có thể nói vậy, sự di truyền của các sinh vật để khiến chúng phục vụ nhu cầu của chúng ta tốt hơn?