Which of the following does not cause pollution ?

examrobotsa's picture
Q: 73 (SSC/NA)

Which of the following does not cause pollution ?

question_subject: 

Science

question_exam: 

SSC

stats: 

0,21,2,1,21,0,1

keywords: 

{'pollution': [3, 0, 1, 0], 'petrol': [2, 0, 1, 5], 'solar energy': [6, 1, 0, 3]}