单项选择题 Which of the following is not one of the basic political systems of our country? （ ） A.The system of regional ethnic autonomyB.The system of community-level self-governanceC.The system of CPC-led multiparty cooperation and political consultationD.The system of people’s congresses
单项选择题 属于下呼吸道的是()A．口腔B．鼻C．咽D．喉E．气管
单项选择题 轮回选择通过对群体中个体的选择和杂交重组，不断打破原有群体的遗传平衡，再通过随机交配使其达到新的平衡使群体中的优良基因频率不断提高，群体不断得到改良。（ ）A.对B.错