21. For the purposes of this Part, except sections 752.0.1 to 752.0.7,(a) persons are connected by blood relationship if one is the child, other descendant, brother or sister of the other;
(b) persons are connected by marriage if one is married to the other or to a person connected with the other by blood relationship or by adoption; and
(c) persons are connected by adoption if one has been adopted, either legally or in fact, and would be connected with the other by blood relationship or by marriage if filiation by adoption were filiation by blood.