切洋葱时会闻到一种辣味,该辣味物质存在于( )
A.细胞核
B.细胞质
C.液泡
D.细胞壁
液泡内含有细胞液,溶解着多种物质,有多种味道:酸、甜、苦、辣.
故选:C
—Flight 331 _______.I’d better be on my way.Goodbye.
—Bye.Happy landing!
A.was announced
B.is being announced
C.has announced
D.is announcing
热红外影像上的阴影是目标地物与背景之间辐射差异造成的,可分为()和()两种。