如图为某生态系统中的食物网示意图，若种群E含有的总能量为8.6×108千焦，种群B含有的总能量为1.7×108千焦，则从理论上讲，种群A至少可获得的能量为（）A．8.6×10千焦B．1.7×-生物

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