[解析]
(1)B.细节理解题.根据第三段内容Fire ants living in Brazilian forests are perfectly at home in an environment where flooding is common.To save themselves,the insects connect their legs together and create floating rafts.Some ant rafts can be up to 20 centimeters wide.可知,本段主要介绍了巴西森林里的火蚁在洪水中的自救方式.故选B.
(2)A.推理判断题.根据第4段可知,机械工程师大卫•胡说"如果有100只蚂蚁,它们就有600只腿,99%的腿将连接到相邻蚂蚁.因此他们非常善于维护这个木筏网."即蚂蚁知道如何紧密连接在一起.故选A.
(3)B.细节理解题.根据倒数第3段The pictures showed that larger ants serve in central positions to which smaller ants hold.The larger ants create pockets of air that keep the insects afloat.可知,图象显示较大的蚂蚁在中央位置,它们以较小蚂蚁为支撑.较大的蚂蚁形成致使蚂蚁浮动的气囊,创建洪水期间的浮动救生筏.故选B.
(4)C.推理判断题.根据Scientists say small robots or materials that can change shape could be programmed in a similar way,working towards a shared goal.可以推测出,科学家说,可以改变形状的小型机器人或材料可以用类似的方式编程,像蚂蚁一样工作.故选C.