Carbon forms the backbone of every major type of biological molecule, including carbohydrates, fats, proteins, and nucleic acids. How does carbon’s high valence relate to its ability to form these large and complex biomolecules?

Carbon has four electrons in its outermost shell, with these it forms covalent bond with other elements by sharing electrons with them.
The elements that made up the biological molecules react easily with carbon, giving rise to different types of macro molecules. Besides this, carbon is flexible and can conform to any shape whether linear, coiled, ring or ball form.