在现代社会中,作为教育者的幼儿教师角色不包括( )
A. 幼儿的观察者和研究者
B. 公共关系的协调者
C. 幼儿学习的引导者
D. 幼儿的榜样和示范者
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Many important industrial compounds such as ethanol, acetic acid, organic acids, butanol and acetone were being produced by the end of 19th century by microbial fermentation procedures that were open to the environment.
A. 酒精
B. 醋酸
C. 丁醇
D. 丙酮
A new direction in biotechnology came in the 1940s with the introduction of complicated engineering techniques to the mass cultivation of micro-organisms to ensure that the particular biological process could proceed with the exclusion of contaminating micro-organisms.
A. 群体培养
B. 群体文化
C. 大量栽培
D. 群体教化
Thus by prior sterilization of the medium and the bioreactor and with engineering provision for the exclusion of incoming contaminants only the chosen biocatalyst was present in the reactor.
A. 污秽
B. 污染物
C. 杂质
D. 污垢
Manipulation of the genome of industrially important organisms by sexual recombination and by mutation has long been part of the innovative repertoire of the industrial geneticist.
A. 突变
B. 元音变化
C. 改变
D. 变种