Final answer:
When 5 monomers join together to form a polymer, 5 water molecules are produced as byproducts.
Step-by-step explanation:
In a dehydration synthesis reaction, water molecules are released as byproducts when monomers join to form a polymer. Each monomer contributes a hydrogen atom and a hydroxyl group to the reaction. Since 5 monomers are joining together, 5 water molecules would be produced.