Why is carbon so abundant in living things when oxygen is the most abundant element on Earth?

ACarbon atoms can bond with one another to make chains and cyclic structures whereas oxygen atoms cannot form chains or cyclic structures.

BCarbon atoms are found in compounds that are solids at room temperature whereas oxygen atoms are found in compounds that form gases

CCarbon atoms have lower mass than oxygen atoms, which keeps the masses of living things within desirable limits.

DCarbon atoms are more stable than oxygen atoms, which allows living things to have more stable compositions.