NSES Content Standard B  Physical Science: Structure and properties of matter Grades 9-12, page 179 Carbon atoms can bond to one another in chains, rings, and branching networks to form a variety of structures, including synthetic polymers, oils, and the large molecules essential to life.

 
Benchmark 5C The Living Environment: Cells
Grades 9-12, page 114
A living cell is composed of a small number of chemical elements mainly carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur. Carbon, because of its small size and four available bonding electrons, can join to other carbon atoms in chains and rings to form large and complex molecules.