Answer:
The correct answer will be- 19 H₂O molecules.
Step-by-step explanation:
The formation or synthesis of large macromolecules from monomers is a dehydration reaction. During synthesis one -OH from one monomer while one-H from another monomer is released during bond formation. These two ions bind together and form H₂O molecules.
So a bond formation between two monomers releases one H₂O molecule. If the chain has 20 monomers it will have 19 bonds and thus 19 molecules of H₂O will be released.
Thus, 19 H₂O molecules are the correct answer.