Covalent bonds place constraints on the shapes of biological molecules. As the size and complexity of a biomolecule increases, the chemical focus shifts from covalent bonds to noncovalent interactions. Non Covalent interactions dictate the stable, native conformations of large macromolecules and polymers while permitting the flexibility necessary for their biological functions. What characteristics of weak noncovalent interactions enable the assembly, stability, and functions of biomolecules? a. They are not affected by the surrounding aqueous environment. b. They are readily reversible, whereas covalent bonds require a much larger input of energy to break. c. They have a large aggregate strength when multiple interactions are present. d. They are stable, requiring a large amount of energy to break.