In describeing and interpreting human cultures, anthropologists have long relied on the ethnographic fieldwork, comprising participant observation.

a) What makes this research process exclusively challenging and efficient?

Need help in answering the above, specifically related to the given:

1) Challenges linked to interviewing and informants.
2) Challenges linked to gender, both of the subject and anthropologist.
3) Of what use might the findings be for meeting the exclusive challenges of our globalizing world?