A claim for cargo damages may be held against the shipowner if such damage is the result of failure of the ship’s officers to（）. ["ensure the fitness and safety of cargo spaces","ensure adequate packaging of the cargo","prevent delays due to quarantine restrictions","correct all defects in the ship's constructio"]
调频时，如调制信号振幅增大一倍，调制信号频率升高一倍，则最大频（）。 ["不变","增大一倍","减小一倍","增大2倍"]
某零售商从很多批发商处进货，再按照消费者的需求以及所在区域的消费特征配置产品，便于消费者购买。该零售商承担的功能是（）。 ["商品存贮","信息传递","风险承担","商品组合"]
下列有关免疫的说法，正确的是（）。 ["被T细胞识别的抗原不会与抗体结合","抗体可由记忆B细胞产生","浆细胞可以特异性识别抗原","致敏T细胞能使抗原细胞的细胞膜通透性增大子二代中灰兔"]
下列经济业务会影响企业存货周转率的有（） ["收回应收账款","销售产成品","期末购买存货","偿还应付账款"]
简述车轮虫病的流行情况。
