Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Q: Context: Reactive oxygen species are involved in ovulation. The aim of this study was to examine gonadotropin regulation of antioxidant enzyme sulfiredoxin (Srx) and peroxiredoxin 2 (PRDX2) expressions and modification during the ovulatory process in rats. Administration of antioxidants in vivo reduced ovulation rate and cumulus expansion. LH treatment increased H(2)O(2) levels within 15 min, which, in turn, induced Srx gene expression in cultured preovulatory follicles. Treatment of preovulatory follicles with catalase suppressed the stimulatory effect of LH on Akt phosphorylation. LH- or H(2)O(2)-stimulated Srx mRNA levels were suppressed by inhibitors of antioxidant agents and MAPK kinase. An in vivo injection of equine chorionic gonadotropin-human chorionic gonadotropin (hCG) stimulated Srx mRNA within 1 h in granulosa but not thecal cells of preovulatory follicles. Srx protein levels were stimulated from 3 h post-hCG injection. Immunofluorescence analysis revealed that oocytes expressed the Srx protein. Furthermore, hCG treatment increased Srx expression in mural granulosa, theca and cumulus cells, but the Srx protein was not detected in corpora lutea. Gene expression of PRDX2, identified as an Srx-dependent modified enzyme, was stimulated by gonadotropins. In situ hybridization analysis demonstrated that PRDX2 mRNA was detected in oocytes and theca cells as well as granulosa cells of some antral and preovulatory follicles. High levels of PRDX2 mRNA were detected in corpora lutea. Total levels of PRDX2 protein were not changed by gonadotropins. However, levels of hyperoxidized PRDX2 increased within 2-3 h after the hCG injection. Taken together, gonadotropin stimulation of Srx expression and PRDX2 modification in the ovary suggest the existence of an antioxidant system to maintain H(2)O(2) production and elimination during the periovulatory period.
Question: What type of enzyme is peroxiredoxin 2 (PRDX2)?

A: antioxidant
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Q: Context: Ways to travel Modern life is impossible without travelling. The fastest way to travel is by air. With a modern plane you can travel in one day to places which took a month or more one hundred years ago. Travelling by train is slower than by air, but it has its advantages . You can see the country you are travelling in. Modern trains have comfortable seats and dining cars. They make even the longest journey enjoyable. Some people prefer to travel by sea when it is possible. There are large lines and river boats with which you can visit many other countries and different places. Travelling by sea is a very pleasant way to spend a holiday. Many people like to travel by car. You can make your own timetable. You can travel three or four hundred miles or only fifty miles a day, just as you like. You can stop wherever you wish: where there is something interesting to see, at a good restaurant where you can enjoy a good meal, or a hotel to spend the night. That is why travelling by car is popular for pleasure trips, while people usually take a train or a plane when they are travelling on business.
Question: How many ways to travel are mentioned in the passage?

A: four
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Q: Context: Bill Beckwith was involved in a motorcycle accident at the Haight district in San Francisco, California on December 2, 2013, and later died at the local general hospital, aged 38.
Question: What was the cause of death of Bill Beckwith?

A:
accident
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