Which of the following is NOT given as an advantage of using biological agents over chemical herbicides?
Giải bởi Vietjack
Đáp án C
Câu nào sau đây không được nêu lên như một lợi ích của việc sử dụng chất sinh học so với thuốc diệt cỏ hóa học?
A.Chúng an toàn hơn cho công nhân.
B. Chúng ít phá hoại những cây được trồng.
C. Chúng không dễ dàng có sẵn.
D. Chúng không cần phải được sử dụng thường xuyên.
Dẫn chứng: The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.
According to the passage, biological agents mainly consist of________
The remark: “ to have a fast car, you need both a good engine and fuel’’ in the passage means that in order to become a genius, ________
The most successful animals on Earth, human beings, will soon be the only ones (35) ________ unless we can solve this problem.
When does the human body begin to lose vigor and the ability to function efficiently?
The word "Marring" in paragraph 1 is closest in meaning to________
