某研究所对一条河流生态系统进行了几年的跟踪调查,发现某种鱼迁

某研究所对一条河流生态系统进行了几年的跟踪调查,发现某种鱼迁入此生态系统后的种群数量增长速率随时间的变化如右图曲线所示。则在t1时该种群的年龄组成类型为 

A.稳定型w_w+w.k_s_5*u.c_o*m             B.增长型

C.衰退型                D.混合型

答案

B

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