Explanation:
In all living system we can always find basic elements carbon, oxygen, nitrogen and hydrogen, carbon is the basic building unit contained in living matter. The percentage of carbon in the mass of living matter is 19.0% oxygen and hydrogen are present in almost all organic compound which creates living organisms.
There are 7 levels of classification for Animals. Kingdom, Phylum, Classes, Order, Families, Genus, and Species.
The answer would be C. H2O is polar while O2 is nonpolar.