What do side bonds account for in the hair?

Side bonds in hair play a crucial role in determining its strength and elasticity. These bonds include hydrogen bonds, salt bonds, and disulfide bonds, which collectively help maintain the structural integrity of the hair strand.

Strength comes from the disulfide bonds, which are strong covalent bonds formed between the sulfur atoms in the amino acids of keratin, the protein that makes up hair. The presence of these bonds allows hair to withstand stretching and mechanical stress without breaking.

Elasticity is closely linked to the ability of the hair to return to its original shape after being stretched. The balance of side bonds enables hair to maintain its shape while still allowing flexibility.

While the other options address various characteristics of hair, none pertain to the specific roles of side bonds in contributing to the fundamental structural qualities that allow hair to be resilient and flexible. This highlights why the selected answer is particularly relevant to the question at hand.