Question 12
Photosynthesis and Plant NutritionIn an experiment to investigate the effect of nitrogen on the growth of plants, the substrate should be a medium of
- A.washed sand
- B.saw dust
- C.cow dung
- D.clay soil.
Show the answer and explanation
Answer: A (washed sand)
Explanation
The medium must contain no nitrogen of its own so the effect of adding it can be seen; washed sand is nearly free of nutrients. Cow dung and clay soil already contain nitrogen.