题目

图一种群在理想环境中呈“J”型曲线增长（如图中甲）；在有环境阻力条件下呈“S”型曲线增长（如图中乙）。图二为某生态系统中的三个种群（a、b、c）数量的变化如图所示，已知种群c为自养生物。下列有关叙述正确的是        图一                                    图二 A．图一中环境阻力对种群增长的影响出现在d点之后 B．若图一表示蝗虫种群增长曲线，则虫害的防治应在b点开始；若表示草履虫种群增长曲线，当种群 Choose the best response from A to F according to the sentences given.(A man and a woman are talking at the Shanghai Hongqiao Airport)A: Excuse me, sir. Could you tell me how to get to the zoo?B: Sorry, 1. I’m new here. 2. .A: Excuse me, Could you tell me the way to the zoo?C:Go along this street until you reach the second traffic lights,then turn left. At the end of the street, you’ll see the zoo.A : 3.C:Yes ,you can.A: 4. .C: You can take the No.6 bus.A: Thank you very much.C: 5. A. Please ask that girl.B.Which bus shall I take?C.I don’t know.D.Is it far from here?E. Can I take a bus to get there?F.It’s my pleasureG.Don’t thank goodnes.