分类学上,将抹香鲸归类为哺乳动物的主要原因是( )
A.用肺呼吸
B.体温恒定
C.心脏四腔
D.胎生、哺乳
答案:D
Performing ()involves monitoring specific project results to determine if they comply with relevant quality standards and identifying ways to eliminate causes of unsatisfactory results.
A.quality planning
B.quality assurance
C.quality performance
D.quality control
下列关于食管癌的描述错误的是()
A.多见于食管中段
B.早期即可出现明显的吞咽困难
C.腺癌的发生与Barrett食管有关
D.主要为鳞状细胞癌
E.晚期可经血道转移至肝和肺