Q84.
Which of the following adds/add nitrogen to the soil? 1. Excretion of urea by animals 2. Burning of coal by man 3. Death of vegetation Select the correct answer using the codes given below:
Answer
C
Explanation
When animals excrete urea, it is broken down by soil bacteria into ammonia and then nitrates, adding nitrogen to the soil. When vegetation dies, decomposers break down the organic matter returning nitrogen to the soil. Burning of coal does not add nitrogen to soil — it releases CO2 and sulphur compounds, not nitrogen compounds.