Follicle cells in your scalp assemble proteins to build new hair. this most likely involves reactions.

Dehydration Synthesis Reaction

Explanation:

When water participates in a reaction as a product, the process is called a dehydration synthesis reaction, since atoms of H and O are removed from the molecule, which join together to form a water molecule. This occurs at the bonds between amino acids to form proteins. This also occurs when a cell gathers its proteins to create a structure in the body, an example of this occurs when the follicular cells of the scalp gather proteins to create new hair.

thinking it would be d not too sure but i think it's right