Q: 43 (CAPF/2012)

If four balloons A, B, C and D are filled with hydrogen, oxygen, helium and nitrogen gases respectively and left in air, which balloon reaches to the highest distance from the Earth?
question_subject: 
Science
question_year: 
2012
question_exam: 
CAPF
stats: 
0,736,728,736,136,520,72