如图是某同学在探究根的什么部位生长最快时,第一天绘制的根尖各段长度图,请你预测哪一段生长最快?( )
A.1(成熟区)
B.2(伸长区)
C.3(生长点)
D.4(根冠)
答案:B
My hair is shorter than____ . [ ]
A. my little brother
B. him
C. my little brother's
D. he
山梨酸发挥防腐作用的最佳pH为()
A.pH<4
B.pH4.5左右
C.pH<6.0
D.pH<5.0
E.pH6.0~7.5