第25题: [单项选择]The shark's best sense is smell because ______. A. most of its brain is used for this purpose B. it is colour blind C. it can smell blood from a quarter of a mile away D. it can only see up to fifty feet 参考答案:C 答案解析:由第五段中的“Its sense of smell,the function of most of its brain,can detect one part in 600,000 of tuna f