题目

Americans eat _______vegetables per person today as they did in 1910. A. more than twice                     B. as twice as many C. twice as many as                     D. more than twice as many 答案：D下列甲、乙、丙、丁四个图分别表示有关生物学内容，对图中曲线描述正确的是（　　） A、甲图中若a点为茎向光侧的生长素浓度，则b点可能为茎到光侧的生长素浓度B、乙图中若a、c两点所产生的葡萄糖总量相等，则a、c两点的呼吸强度为a大于cC、丙图中a点害虫种群抗药个体所占百分比大于b点害虫种群抗药个体所占百分比D、丁图中影响a、b两点和a、c两点吸收量不同的主要因素分别是载体数量和能量