B细胞接受TI抗原刺激后,产生的抗体主要是
A.高亲和力IgM类抗体
B.低亲和力IgM类抗体
C.高亲和力IgG类抗体
D.低亲和力IgG类抗体
E.低亲和力IgE类抗体
参考答案:B
Which of the following is least likely to be considered a necessary condition for a monopolist to realize profits from price discrimination()
A. A product for which the demand curve is downward sloping.
B. At least two groups of customers, each with a different price elasticity of demand.
C. Two different costs of production.
()是烘丝机的主要部件,其作用是提供和传导热量,对进入的烟丝进行干燥,实现物料的输送。