Given the task definition and input, reply with output. Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.

Question: Is aetiology of stillbirth : unexplored unexplained?
Answer: Postmortem investigation rates are low. They reveal a cause of death for the majority of cases that are unexplained clinically. Epidemiological investigations of unexplained fetal death based on cases not subject to complete postmortem investigation may lead to inaccurate conclusions. A standardised definition for unexplained fetal deaths that distinguishes between cases with detailed investigation and those with limited or no investigation is needed.
no