Given a statement and question, generate the answer to the question such that the answer is contained in the statement.

statement: most species go through vulnerable stages after birthing, question: What stage do most species go through after birthing?
vulnerable

statement: Cystitis can be treated with antibiotics., question: Cystitis can be treated with what?
antibiotics

statement: bone density decreases when osteoclasts are more active than osteoblasts, question: What is more active than osteoblasts?

osteoclasts