Q: 9 (IAS/2013)

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.
question_subject: 
Ecology
question_year: 
2013
question_exam: 
IAS
question_sub_subject: 
Ecology
question_topic: 
Ecology
stats: 
0,6192,4360,1000,360,6152,3040