Weeding is necessary because
(a) They affect the growth of the plant
(b) They affect the nutrients supplied to the soil
(c) Both (a) and (b)
(d) None of these

Hint: Weeds are those unwanted plants that grow along with the main crop in the crop fields. They are very strong and dominating competitors for main crops. They mainly compete for essential components required for the growth and development of the crops.

Complete answer:
Weeding means removal or cutting down of unwanted plants or weeds. It is necessary because they affect the growth of the plant and also the nutrients supplied to the soil. Weeds compete with the main plant not only for space but also for water and nutrients.
As weeds also absorb nutrients from the soil they damage the main crop because they are unable to get the proper amount of nutrition from the soil.
Similarly, it damages the main plant in case of light, water absorption, and space occupied by the weeds.
Weeding also helps in loosening the soil if it is done by the process of handpicking.
Weeding can also be done by the use of chemicals such as MCPA, 2,4-D, etc
Some examples of common weeds are grass, algae, amaranthus, chenopodium, Xanthium, parthenium, chmicus rotundus, etc.

So, the correct answer is,’ both (a) and (b)’.

Note: -Weeds not only reduce the yield of the crop but sometimes they become the sources of diseases also.
-Weedicides and herbicides are most commonly used nowadays and considered as effective ways of weeding. They can also be applied at three stages such as before and after the planting of crops and also after the emergence of weeds.
-The weedicides may lead to health hazards and also can create some environmental issues.