5. What happens in a condensation reaction? cross-linking of monomers head-to-tail joining of monomers side-by-side joining of monomers substitution of a halogen on monomers

The answer is head-to-tail joining of monomers. Monomer used in condensation have two functional groups that combine to form amide and ester linkages. When this reaction occurs, water molecules is removed and that is why it is called a condensation reaction.