Many opsonins are multimeric (as opposed to monomeric) molecules [complete the sentence and assess the resulting statements (61-66) describing various hypothetical conclusions as either factually correct (= "true") or incorrect (= "false")]:

so that they can be regulated allosterically.

because they are all derived from the same proto-opsonin.

and, therefore, their phagocytosis-inhibiting activities are reduced.

- one subunit binds pathogen and the other has enzymatic activity.

and thus can bind repeating structures on pathogen surfaces.

because they have to crosslink receptors on phagocytes in order for phagocytosis to occur.