问题详情

阅读文章，回答下列各题： "I would tell anyone who s thinkingabout going back to school that it s not as difficult as you think," saysKaren Jonaitis, a woman, last year, at 47, earned a bachelor s degree inbusiness administration at a college. "I realized that I would not move upin my career without a degree. " A generation ago, Jonaitis would have beena rarity(稀罕)incollege. Today about 6 million people aged25 or older are studying in Americaninstitutions of higher learning. Whether they are returning to improve jobskills or for the love of learning, adults no longer see age as a deterrent(障碍).Most people jump at the oppor- tunity to do something new. Some ofthem make changes they d been thinking about all their lives. Others re- turnto school out of economic necessity. New developments in neuroscience(神经科学)and psychology areconfiring that there are few age limits on how much the brain can absorb and for how long--if you stay active.Continuing to learn keeps us mentally in shapeand able to learn more. On mental tests, experts discovered, half to two-thirdsof the people in their 70s were as intellectually quick as people in their 30s.Those who fell below average tended to be people who had not made a lifelonghabit of reading. They also were less physically active. Many adult students say learning is easierfor them today. They bring different skills to the classroom, and they reless upset if something goes wrong. They have a real thirst, a real desire tolearn. A life-long habit of reading and physicalactvifies can keep_________________in good condition.
A.our mind
B.our body
C.our age
D.our nerves请帮忙给出正确答案和分析，谢谢！