What is the main conflict in State of Wonder by Ann Patchett?

Marina Singh, a doctor, is sent into the Amazon jungle to investigate the death of her coworker, and to check the progress of an ongoing research study, conducted by a mentor of hers, Dr. Swenson. However, Marina finds instead a puzzle in ethics, morality, and humanity that forces her to rethink her own positions in life and asks readers to do the same.