(N/A) $(i)$ Unwanted plants that grow along with cultivated crops in fields are called weeds. Examples: $Xanthium$ (gokhru) and $Parthenium$ (gajar grass).
$(ii)$ Weeds compete with crop plants for essential resources like nutrients, space, water, and sunlight. By consuming these resources, they reduce the growth and yield of the main crop. Therefore, removing them during the early stages of crop growth is crucial to ensure the crop gets sufficient resources for a healthy harvest.
$(iii)$ Five preventive methods for weed control are:
$(a)$ Proper preparation of the seedbed.
$(b)$ Timely sowing of seeds.
$(c)$ Intercropping.
$(d)$ Crop rotation.
$(e)$ Summer ploughing.