产肠毒素大肠埃希菌会引起人和动物腹泻,肠毒素基因主要存在于()
A. F因子
B. R因子
Col质粒
D. V质粒
E. Ti质粒
A source of supply can operate in a perfectly competitive market, an oligopoly, or in a monopoly market. What activity identifies which one it is?
A. Conduct a market analysis
B. Process all possible sources
C. Decide whether to make or buy
D. Choose a supplier
微信支付 
支付宝支付