Question

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of

the milder acts 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

crop loss; they compete for sunlight, nutrients, and water with useful plants. The global need for weed

control has been answered mainly by the chemical industry. Its herbicides are elective and sometimes

necessary, but some pose serious problems, particularly, if misused. Toxic compounds threaten animal and

public health when they accumulate in food plants, ground water 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 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 muddied 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.

(a) Complete the following statements (Marks 3 x 1 = 3)

(i) The topic dealt with in the passage is ______________

(1) The importance of chemical industry

(2) The dangers of toxic chemicals

(3) Advantages of biological agents over chemicals

(4) A proposal to ban the use of all herbicides

(ii) According to the passage, biological agents consist of__________________

(1) Insects and microorganisms

(2) Useful plants

(3) Weed

(4) Herbicides

(iii) A simple damaging effect of weeds is seen in​

Answer 1

Answer:

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of

the milder acts 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

crop loss; they compete for sunlight, nutrients, and water with useful plants. The global need for weed