题目

阅读理解 Zebra crossings－the alternating dark and light stripes on the road surface－are meant to remind drivers that pedestrians may be trying to get across. Unfortunately, they are not very effective. A 1998 study done by the Department of Traffic Planning and Engineering at Sweden's Lund University revealed that three out of four drivers maintained the same speed or even speeded up as they were approaching a crossing. Even worse, only 5% stopped even when they saw someone trying to get across. Now a mother-daughter team in Ahmedabad, India has come up with a clever way to get drivers有关生命系统的结构层次的表述，下列正确的是（ ）A. 病毒是能进行生命活动的最小系统B. 一棵小叶榕树与一只老虎，在生命系统中具有相同的层次C. 一片农田中的所有动、植物个体组成了一个群落D. 实验室中某个培养基上长出的一个大肠杆菌菌落是一个种群