Final answer:
Participant observation provides anthropologists firsthand accounts of marriage ceremonies and deeper insight into the cultural significance of marriage customs.
Step-by-step explanation:
Participants' observations can help an anthropologist gain an understanding of a culture's marriage customs by providing firsthand accounts of marriage ceremonies. Through participant observation, anthropologists immerse themselves in the culture, directly participating in activities and observing events, which allows for a deeper insight into the cultural practices and the meaning behind them. Not only does this method provide detailed descriptions of the customs, but it also highlights the implicit knowledge and attitudes of the individuals within the culture regarding marriage.