Final answer:
The correct answer to the question is B. Condensation, which describes reactions that join subunits into larger molecules while removing a water molecule, also known as dehydration synthesis.
Step-by-step explanation:
Reactions that remove the equivalent of a water molecule when subunits are joined to form a larger molecule are referred to as dehydration synthesis or condensation reactions. In these reactions, two subunits, or monomers, covalently bond to each other to form polymers, releasing a water molecule as a byproduct. For example, during dehydration synthesis, a hydrogen atom is contributed by one monomer and a hydroxyl group (OH) from another, and as they combine to form a new covalent bond, they release a water molecule.
In the context of macromolecules, dehydration synthesis is a critical and recurrent process. Repeated condensation reactions between monomers, such as amino acids, form larger structures like polypeptides during translation. Hence, the correct answer to the student's question is B. Condensation, which is synonymous with dehydration synthesis in this scenario.