Acondensation polymerization reaction produces a polymer and 1) h2 2) o2 3) co2 4) h2o

            Option-4 (H₂O) is the correct answer.

Explanation:
                   Condensation reactions are those reactions in which two molecules combine to form a macromolecule with the elimination of small molecules like H₂O, HCl, ROH as a byproduct.

Example:
              Amino acids (monomers) join together to form protein (polymer) with the elimination of H₂O molecules.