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.

[Q]: Question: Does renal excretion of fluoride after fluoride mouth rinse in children?
Answer: After the use of a fluoride mouthwash, in children, there is a statistically significant increase of fluoride ion in urine, which can be attributed to the application of this product.
[A]: yes


[Q]: Question: Is unexplained elevated maternal serum alpha-fetoprotein predictive of adverse perinatal outcome in an indigent urban population?
Answer: Elevated maternal serum alpha-fetoprotein levels offer little if any additional predictive value for adverse perinatal outcome in populations already at high risk for such outcomes on the basis of obstetric or socioeconomic criteria.
[A]: no


[Q]: Question: Does the Boston keratoprosthesis provide a wide depth of focus?
Answer: The KPro's wide depth-of-focus makes the visual acuity less dependent on an exact refractive correction at distance and explains the 'pseudoaccomodation' experienced by these patients. This is primarily due to the small pupil diameter of the KPro. The current manufacturing steps in 0.50 dioptre increments appears to be sufficient.
[A]:
yes