2016 · Q29
The elemental composition of an adult human body by mass is
General KnowledgeChemistry
- AC > O > H > N
- BO > C > H > N
- CN > C > H > O
- DN > C > O > H
Explanation
By mass, the adult human body is about 65% oxygen (mostly in water), 18% carbon, 10% hydrogen and 3% nitrogen. The descending order is therefore O > C > H > N. The alternatives wrongly put carbon or nitrogen first, contradicting the dominance of water in body mass.