When two monomers join to build a polymer, the small molecule released is:

1. Polymers are assembled by dehydration synthesis reactions. 2. The name means 'to put together while losing water'. 3. One monomer gives up a hydroxyl group and the other a hydrogen, and these leave together. 4. The molecule released is therefore water. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 3 'Biological Macromolecules', sections 3.1-3.5_