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.

[EX Q]: Question: Does bone mineral density vary as a function of the rate of joint space narrowing in the hip?
Answer: Patients with a rapid rate of JSN of the asymptomatic hip after unilateral THR are characterized by elevated local and remote BMD. The local elevation in BMD implies that increased local bone density may contribute to or serve as a marker for increased risk of development of OA (assuming that JSN can be used as a predictive marker). The presence of elevated BMD in the spine suggests that there are systemic as well as local aspects of OA pathogenesis, at least in patients with one THR and rapid JSN in the contralateral hip.
[EX A]: yes

[EX Q]: Question: Do a Profilometric Study to Assess the Role of Toothbrush and Toothpaste in Abrasion Process?
Answer: Besides supporting the fact that toothpaste is needed to create a significant abrasion, this study also showed that a softer toothbrush can cause more abrasion than harder ones. The flexibility of bristles is only secondary to abrasion process and abrasivity of dentifrice has an important role in abrasion process.
[EX A]: yes

[EX Q]: Question: Do inflammatory cytokines promote the retrodifferentiation of tumor-derived hepatocyte-like cells to progenitor cells?
Answer: Cancer progenitor cells (or metastasis progenitors) may derive from tumor-derived hepatocyte-like cells in an inflammatory environment that is frequently associated with HCC.
[EX A]:
yes