Question 77

The tiny grains of pigment in the cortex that provide natural color to the hair are composed of melanin.

Melanin is the pigment responsible for the natural color of hair, found within the cortex. These tiny grains of melanin absorb and reflect light, which ultimately determines the hair's color.

A) keratin.

Keratin is a fibrous protein that forms the structure of hair, skin, and nails. While it is a crucial component of hair's physical makeup, it does not provide color; therefore, it is incorrect in the context of this question regarding pigmentation.

B) melanin.

Melanin is indeed the correct answer, as it is the natural pigment found in the hair cortex that gives hair its color. The presence of melanin in varying amounts and types leads to the diverse range of hair colors observed in individuals.

C) side bonds.

Side bonds refer to the connections between the protein chains in hair that contribute to its strength and structure. These bonds do not play a role in determining hair color, making this option incorrect in relation to the question asked.

D) polypeptides.

Polypeptides are chains of amino acids that make up proteins, including keratin. While they are fundamental to the hair's structure, they do not contribute to the pigmentation of hair, thus rendering this option incorrect.

Conclusion

Melanin is the definitive answer as it directly relates to the pigmentation of hair, being responsible for its color. The other options, while important to hair structure and function, do not provide any coloration, making them unsuitable answers for this specific question.