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.

Which of the following statements about the use of chemical agents as herbicides would the author most likely agree?

Câu hỏi liên quan

• According to the passage, who was the first person to use artificial refrigeration for a practical purpose?

• The phrase “more achievement oriented” in the paragraph 6 is closest in meaning to ______.

• According to the article, what is unusual about the band Four Square?

ZUNIA12

• The word "hyperactive" is closest in meaning to _____.

• Which sentence about Joseph Pulitzer is NOT true according to the reading passage?

• The series was designed _____________

• The phrase "split off" in paragraph 2 is closest in meaning to ........

• According to the passage,which of the following is a universal rule of etiquette?

• What does the passage mainly discuss?

• With which of the following statements would the author agree?

• What will happen if a dodder plant starts growing where there are no other plants around?

• The word “sustain” in paragraph 3 is closest in meaning to__________.

• Normal human beings .................

• In the 2^nd paragraph, what weakness in nineteenth-century histories does the author point out?

• According to the passage, the way to stop water pollution is ...........

• According to the passage, Pilgrims are ______.

• According to the passage, one exceedingly clever student has ___________

• Psychological reasons for wearing garments include _______.

• Education in early times was mostly aimed at _______.

• The Beatles stopped their live performances because .............