Scientists studied the uptake of potassium ions from chemical fertilisers by wheat plants.
The results are shown.
What is the difference in the uptake of potassium ions at 360 days after planting compared to 30 days after planting?
▶️ Answer/Explanation
Ans: C
At 30 days: ~75 kg/ha. At 360 days: ~360 kg/ha. Difference = 360 – 75 = 285 kg/ha. The graph shows a steady increase, with the highest uptake at 360 days.
How do herbicides help to increase food production?
A) by increasing biodiversity
B) by killing insect pests
C) by providing nutrients
D) by reducing competition
▶️ Answer/Explanation
Ans: D
Herbicides increase food production primarily by eliminating weeds (D: reducing competition). This allows crops to access more water, nutrients, and sunlight without competing with unwanted plants.
Option A is incorrect as herbicides typically reduce biodiversity by targeting specific plants. Option B describes insecticides, not herbicides. Option C is false as herbicides don’t provide nutrients; fertilizers do.