Detailed Instructions: 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.
Problem:Question: Does endothelin A receptor blockade alter PSA secretion in prostate cancer cell lines?
Answer: Blockade of the ETA receptor does not affect the secretion of PSA in prostate cancer cell lines.
Solution:
no