Final answer:
The usual minister of the Sacrament of Baptism is a priest, but in cases of necessity, any person can baptize as long as they use the correct matter and form.
Step-by-step explanation:
The usual minister of the Sacrament of Baptism is a priest. However, there are situations in which someone else can baptize. One such situation is a case of necessity, where there is no priest available. In such cases, any person, even a layman, can baptize as long as they use the correct matter and form of the sacrament. For example, if a group of laymen were stranded in a desert and agreed to elect one of them to baptize, that person would be a valid minister of the sacrament.