Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants. The global need for weed control had been answered mainly by the chemical industry. Its ...
Phạm Văn Phú | Chat Online | |
07/09 17:24:42 (Tiếng Anh - Lớp 12) |
Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.
The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.
In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.
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.
With what topic does this passage primarily deal?
Lựa chọn một trả lời để xem Đáp án chính xác Báo sai đáp án hoặc câu hỏi |
A. The importance of the chemical industry 0 % | 0 phiếu |
B. The dangers of toxic chemicals 0 % | 0 phiếu |
C. A proposal to ban the use of all herbicides 0 % | 0 phiếu |
D. Advantages of biological agents over chemical ones 0 % | 0 phiếu |
Tổng cộng: | 0 trả lời |
Trắc nghiệm liên quan
- Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. ... (Tiếng Anh - Lớp 12)
- Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. ... (Tiếng Anh - Lớp 12)
- Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. ... (Tiếng Anh - Lớp 12)
- Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. ... (Tiếng Anh - Lớp 12)
- Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in ... (Tiếng Anh - Lớp 12)
- Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in ... (Tiếng Anh - Lớp 12)
- Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in ... (Tiếng Anh - Lớp 12)
- Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in ... (Tiếng Anh - Lớp 12)
- Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in ... (Tiếng Anh - Lớp 12)
- Mickey Mantle was one of the greatest baseball players of all time. He played for the New York Yankees in their years of glory. From the time Mantle began to play professionally in 1951 to his last year in 1968, baseball was the most popular game in ... (Tiếng Anh - Lớp 12)
Trắc nghiệm mới nhất
- Four phrases/sentences have been removed from the text below. For each question, mark the letter A, B, C, or D on your answer sheet to indicate the correct option that best fits each of the numbered blanks from 37 to 40. England’s traditions have ... (Tiếng Anh - Lớp 9)
- 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 following questions from 31 to 36. British English and American English are two variations of the English language that ... (Tiếng Anh - Lớp 9)
- What does the notice say? (Tiếng Anh - Lớp 9)
- Read the following sign or notice and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. What does the sign say? (Tiếng Anh - Lớp 9)
- Laura/ suggested/ go skiing/ the/ Alps/ Christmas. (Tiếng Anh - Lớp 9)
- Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is made from the given cues in each of the following questions. Lucy and I/ different opinions/ but/ we/ still/ get/ each other. (Tiếng Anh - Lớp 9)
- Let’s drink some warm water after eating spicy food. (Tiếng Anh - Lớp 9)
- Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to the original sentence in each of the following questions. “I’m busy with my work all day today,” his dad said. (Tiếng Anh - Lớp 9)
- Mark the letter A, B, C, or D on your answer sheet to indicate the correct option that best fits each of the numbered blanks from 19 to 24. Living in the mountains can be very hard. First, there is (19) _______ to grow crops or raise livestock. (20) ... (Tiếng Anh - Lớp 9)
- Choose the sentence that can end the text (in Question 17) most appropriately. (Tiếng Anh - Lớp 9)