A:16
B:12
C:8
D:0
— How do you like the regulations of our school?
— The regulations are strict with the students and they require that students _______ at least 90% of the lectures.
某种酶是由419个氨基酸形成的蛋白质。科学家利用生物技术做出5种不同长度的该酶的片段,并分别测定其活性如图所示,分析该酶最可能具有活性的部分是( )