[解析]
(1)B.细节理解题。根据第一段中的"Exercise early in life seems to have lifelong benefits for the brain,in rats at least."可知,锻炼对大脑终生有好处,至少对老鼠是这样的。可知研究表明,老鼠年轻时运动越多,年老时记忆力越好故选B.
(2)D.推理判断题。根据第三段和第四段"Wojtowicz's team divided 80 young male rats into two equal groups,and placed running wheels in the cages of one group for a period of six weeks.Around four months later﹣when the rats had reached middle age﹣the team taught all the rats to connect an electric shock with being in a specific box.When placed in the box,they froze with fear.Two weeks later,the team tested the rats in three situations:exactly the same box in the same room,the same box with the room arranged differently,and a completely different box in a different room.Wojtowicz 的研究小组将80只雄性幼鼠分成两组,在一组的笼子里放置跑轮,为期六周。大约四个月后,当老鼠到达中年时,研究小组教会所有的老鼠将电击与放在一个特定的盒子里联系起来。当他们被放进盒子里时,他们吓呆了。两周后,研究小组在三种情况下测试老鼠:完全相同的盒子在同一个房间,相同的盒子与房间的布局不同,和一个完全不同的盒子在不同的房间。"可知这两段讲述Wojtowicz的研究小组对老鼠进行试验的过程,因此通过描述过程发展的。故选D.
(3)D.代词指代题。根据第二段" "This is an animal study,but it shows that physical activity at a young age is very important﹣not just for physical development,but for the whole lifelong track of cognitive(认知的)development during ageing," says Martin Wojtowicz of the University of Toronto,Canada. "In humans,it may delay the appearance of Alzheimer's symptoms(阿茨海默氏症),possibly to the point of preventing them."加拿大多伦多大学的 Martin Wojtowicz 说: "这是一项动物研究,但它表明年轻时的体育活动是非常重要的﹣﹣不仅对于身体发育,而且对于老年期认知发展的整个终身轨迹都非常重要。"对人类来说,它可以延缓老年痴呆症的出现,可能达到预防的效果"。"可知本段介绍一项动物研究,具体的运动对身体的发育很重要,对于人类,它可能会推迟阿兹海默氏症的出现。因此it在句中指的是具体的身体活动,也就是锻炼。故选D.
(4)C.观点态度题。根据短文中对这项老鼠实验的过程及其结果的介绍,用数据表示,可见作者对动物研究的态度是很客观的。A.Negative消极的;B.Critical批评的;C.Objective客观的;D.Doubtful怀疑的。故选C.