问题
选择题
People try to avoid public transportation delays by using their own cars , and this _____ creates
further problems . [ ]
A. in short
B. in case
C. in doubt
D. in turn
答案
答案:D
People try to avoid public transportation delays by using their own cars , and this _____ creates
further problems . [ ]
A. in short
B. in case
C. in doubt
D. in turn
答案:D
下表是一个相对封闭的生态系统中五种生物体内残留的有机汞情况,下面是根据表中有关数据作出的一些分析,其中与表中数据相符合的是( )
生物体 | 甲 | 乙 | 丙 | 丁 | 戊 |
有机汞浓度( ppm) | 7 | 0.51 | 0. 39 | 68 | 0.05 |
A.该生态系统的食物链是:戊→乙→丙→甲→丁
B.
该生态系统的能量金字塔如图所示
C.该生态系统中除去甲和丁后,乙与丙的数量会持续增加
D.该生态系统中数量最多的生物是戊,它一定是初级消费者