Some people ski（滑雪） down mountains．Others climb huge rocks or photograph dangerous animals．Why do people enjoy risky activities like these？

Some people take risks simply because it makes them feel good．Psychologist（心理学家）Marvin says that this kind of explorers（探险者） are always looking for change and excitement．When people do something new or risky，a chemical（化学物质） in the brain creates a pleasant feeling．They love this feeling and want to experience itas often as possible．

Other people don't take risks for the feeling of excitement but to achieve a goal．For example，Mike Fay went on a dangerous 2，000﹣mile special journey in central Africa．He worked to help save the wildlife there．Fay's expeditionshelped create 13 national parks．

For other people，such as extreme athletes（极限运动员），taking risks is part of their job．Sports psychologist Shane says extreme athletes see the world differently．In a dangerous activity，most people probably do not feel in control．Extreme athletes are different：they feel in control in dangerous situations．The danger can even help them．For example，skier Daron Rahlves says that being afraid makes him try harder to succeed．

Most of us are not extreme athletes or explorers．However，we still take risks in our lives．Some of us take social risks，such as speaking in front of a large group of people．Sometimes，we take financial risks，such as buying a house．And sometimes we take career risks，such as leaving a job or starting a business．Most people take risks in some areas of life，but not in others．What kind of risk﹣taker are you？

（1）What does the underlined word "it" in Paragraph 2 refer to？ 　　

A．	The brain．
B．	Something new．
C．	A chemical．
D．	A pleasant feeling．

（2）What does the underlined word "expedition" in Paragraph 3 mean？ 　　

A．	Much money．
B．	A journey with a special goal．
C．	A great idea．
D．	A plan for a dangerous journey．

（3）How many kinds of extreme athletes or explorers are mentioned in the passage？ 　　

A．	Three．
B．	Four．
C．	Five．
D．	Six．

（4）Which of the following is true according to the passage？ 　　

A．	Mike Fay is a professional risk﹣taker．
B．	Most people don't take risks in their daily life．
C．	Extreme athletes deal with danger better than others．
D．	Daron Rahlves takes risks mainly for change and excitement．